Vol. 107 No. 3-4 September-December 1978

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersSegundo V. Roxas, Gerardo P. Sicat, Onofre D. Corpus

Roberto V. Ongpin, Geronimo Z. Velasco, Emmanuel V. Soriano

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionGuillermo A. PecacheCommisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 107 No. 1-2 March-June 1978

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersSegundo V. Roxas, Gerardo P. Sicat, Onofre D. Corpus

Roberto V. Ongpin, Geronimo Z. Velasco, Emmanuel V. Soriano

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionGuillermo A. PecacheCommisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 106 No. 3-4 September-December 1977

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersSegundo V. Roxas, Gerardo P. Sicat, Onofre D. Corpus

Roberto V. Ongpin, Geronimo Z. Velasco, Emmanuel V. Soriano

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionGuillermo A. PecacheCommisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 106 No. 1-4 March-June 1977

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionGuillermo A. PecacheCommisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 105 No. 4 December 1976

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 105 No. 3 September 1976

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 104 No. 1-2 March-June 1976

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Institute of Science and TechnologyVedasto R. JoseCommisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Commisioner

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Managing Editor

Ronald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 104 No. 3-4 September-December 1975

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Commisioner

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 104 No. 1-2 March-June 1975

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira B.S.C.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 103 No. 4 December 1974

National Science Development BoardBoard of Governors

Melecio S. Magno,Chairman

MembersGerardo P. Sicat,; Onofre D. Corpuz.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.CommisionerNational Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 103 No. 3 September 1974

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya,Ph.D.; Salvador P. Lopez,Ph.D.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolang, Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira, B.S.C.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 103 No. 2 June 1974

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya,Ph.D.; Salvador P. Lopez,Ph.D.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolangm Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira, B.S.C.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 103 No. 1 March 1974

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya,Ph.D.; Salvador P. Lopez,Ph.D.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolangm Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira, B.S.C.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 102 No. 3-4 September-December 1973

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya,Ph.D.; Salvador P. Lopez,Ph.D.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolangm Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorRonald M. Henson

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 102 No. 1-2 March-June 1973

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya,Ph.D.; Salvador P. Lopez,Ph.D.; Juan Manuel, Ph.D.

Agencies of the Board

Commision on VolcanologyGregorio C. Andal, M.S.Officer-in-Charge

Food Nutrition Research CenterCarmen Ll. Intengan, Ph.D.Acting Director

Forest Products Research and Industries Development CommissionFrancisco Tamolangm Ph.D.Commissioner

National Institute of Science and TechnologyJose Velasco, Ph.D.Commisioner

National Pollution Control CommisionReynaldo Lesaca, Ph.D.Commisioner

Philippine Atomic Energy CommisionLibrado Ibe, Ph.D.Commisioner

Philippine Textile Research InstituteFelipe Ll. Santillan, B.S.M.E.Officer-in-Charge

Philippine Textile Research InstituteRicardo C. Cruz, M.S.Acting Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M

.Associate Editor

Rodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira, B.S.C.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D

Vol. 101 No. 3-4 September-December 1972

National Science Development BoardBoard of Governors

Florencio A. Medina, M.S., M.D.,Chairman

MembersJaime C. Laya, Salvador P. Lopez, Juan Manuel

Agencies of the Board

Commision on VolcanologyGregorio C. AndalOfficer-in-Charge

Food Nutrition Research CenterCarmen Ll. IntenganActing Director

Forest Products Research and Industries Development CommissionFrancisco TamolangCommissioner

National Institute of Science and TechnologyJose VelascoCommisioner

National Pollution Control CommisionReynaldo LesacaCommisioner

Philippine Atomic Energy CommisionLibrado IbeCommisioner

Philippine Textile Research InstituteFelipe Ll. SantillanOfficer-in-Charge

Philippine Textile Research InstituteRicardo C. CruzActing Director

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

[Entered at the post office at Manila, Philippines, as second-class matter.]

Acting EditorIleana R,F, Cruz, A.M.

Associate EditorRodolfo F. FLorentino, M.D., Ph.D. and Higino Ibarra, Ph.D.

Managing EditorAngel Y. Lira, B.S.E.

Contributing Editor

Josefina Cortes, Ph.D.Carmen Ll. Intengan, Ph.D.Josefina B. Jayme, M.D., M.P.NIbarra Santos, Ph.D.

Vol. 101 No. 1-2 Marc h-June 1972

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Librado D. Ibe, Ph.D.Jose M. Lawas, Ph.D.Salvador P. Lopez, Ph.D.

George T. Marcelo, B.S.B.A.Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerAgricultural Research Center

Clare R. Baltazar, Ph.D.Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterVictoria A. Masiluñgan, Phar. D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorAntonio D. Alonte, M.S.; Ireana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureFaustino S. Mensalvas, D.V.M.Faustino S. Orillo, Ph.DEdilberto D. Reyes, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.Frank Lynch, Ph.D.E. Arsenio E. Manuel, M.A.

Botany .Jose Vera Santos, Ph.D.Magdalena Cantoria, Ph.D.Benito S. Vergara, Ph.D.

ChemistryWendel Y. Lim, Ph.D.Bienvenido T. Miranda, Ph.D.Alfredo C. Santos, Ph.D.

NutritionCarmen J.L. Intengan, Ph.D.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Emmanuel Tamesis, Ph.D.Mateo H. Tupaz, Ph.D.

MedicineLetica T. Angeles, M.S.Solita Camara-Besa, M.D.Conrado S. Dayrit, M.D.Victor Valenzuela, M.D.

MicrobiologyLourdes E. Campos, M.D.

Nuclear ScienceManuel R. Euginio, Ph.D.Ibarra Santos, Ph.D.Joser Torres, M.S.

ZoologyCarmen G. Kanapi, Ph.D.Elvira Tan, Ph.D.Carmen C. Velasques, Ph.D.

Vol. 100 No. 3-4 September-December 1971

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Librado D. Ibe, Ph.D.Jose M. Lawas, Ph.D.Salvador P. Lopez, Ph.D.

George T. Marcelo, B.S.B.A.Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., Commisioner\Edilberto D. Reyes, Ph.D., Officer-in-Charge

Office of the Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterVictoria A. Masiluñgan, Phar. D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorAntonio D. Alonte, M.S.; Ireana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureFaustino S. Mensalvas, D.V.M.Faustino S. Orillo, Ph.DEdilberto D. Reyes, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.Frank Lynch, Ph.D.E. Arsenio E. Manuel, M.A.

Botany .Jose Vera Santos, Ph.D.Magdalena Cantoria, Ph.D.

Benito S. Vergara, Ph.D.Chemistry

Wendel Y. Lim, Ph.D.Bienvenido T. Miranda, Ph.D.Alfredo C. Santos, Ph.D.

NutritionCarmen J.L. Intengan, Ph.D.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.

Emmanuel Tamesis, Ph.D.Mateo H. Tupaz, Ph.D.

MedicineLetica T. Angeles, M.S.Solita Camara-Besa, M.D.Conrado S. Dayrit, M.D.Victor Valenzuela, M.D.

MicrobiologyLourdes E. Campos, M.D.

Nuclear ScienceManuel R. Euginio, Ph.D.Ibarra Santos, Ph.D.Joser Torres, M.S.

Zoology

Carmen G. Kanapi, Ph.D.Elvira Tan, Ph.D.Carmen C. Velasques, Ph.D.

Vol. 100 No. 2 June 1971

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Librado D. Ibe, Ph.D.Jose M. Lawas, Ph.D.Salvador P. Lopez, Ph.D.

George T. Marcelo, B.S.B.A.Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterVictoria A. Masiluñgan, Phar. D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorIreana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureFaustino S. Mensalvas, D.V.M.Faustino S. Orillo, Ph.DEdilverto D. Reyes, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.Frank Lynch, Ph.D.E. Arsenio E. Manuel, M.A.

Botany .Jose Vera Santos, Ph.D.Magdalena Cantoria, Ph.D.Benito S. Vergara, Ph.D.

ChemistryWendel Y. Lim, Ph.D.Bienvenido T. Miranda, Ph.D.Alfredo C. Santos, Ph.D.

NutritionCarmen J.L. Intengan, Ph.D.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Emmanuel Tamesis, Ph.D.Mateo H. Tupaz, Ph.D.

MedicineLetica T. Angeles, M.S.Solita Camara-Besa, M.D.Conrado S. Dayrit, M.D.Victor Valenzuela, M.D.

MicrobiologyLourdes E. Campos, M.D.

Nuclear ScienceManuel R. Euginio, Ph.D.Ibarra Santos, Ph.D.Joser Torres, M.S.

ZoologyCarmen G. Kanapi, Ph.D.Elvira Tan, Ph.D.

Carmen C. Velasques, Ph.D.

Vol. 100 No. 1 March 1971

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Constancio M. Ancheta, Ph.D.George T. Marcelo, B.S.B.A.

Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorIreana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.

ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

MedicinePaulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.

Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.S.

Vol. 99 No. 3-4 September-December 1970

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Constancio M. Ancheta, Ph.D.George T. Marcelo, B.S.B.A.

Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorIreana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.

ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

MedicinePaulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.

Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.S.

Vol. 99 No. 1-2 March-June 1969

National Science Development Board

Florencio A. Medina, M.S., M.D.,ChairmanPedro G. Afable, B.S.C.E.

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E.Constancio M. Ancheta, Ph.D.George T. Marcelo, B.S.B.A.

Manuel R. Monsalud, B.S.S.T.Juan Salcedo, Jr. M.S., M.D.Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Clare R. Baltazar, Ph.D., EditorIreana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.

ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

MedicinePaulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.

Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.S

Vol. 98 No. 3-4 September-December 1969

National Science Development Board

Juan S. Salcedo, Jr., M.S., M.D.,ChairmanDiminador O. Reyes.,Ll. B.,

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E. George T. Marcelo, B.S.B.A.Constacio M. Ancheta, Ph.D. Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Carmen Ll. Intengan, Ph.D., EditorClare Baltazar, Ph.D.; Ireana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

MedicinePaulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.S

Vol. 98 No. 2 June 1969

National Science Development Board

Juan S. Salcedo, Jr., M.S., M.D.,ChairmanDiminador O. Reyes.,Ll. B.,

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E. George T. Marcelo, B.S.B.A.Constacio M. Ancheta, Ph.D. Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Carmen Ll. Intengan, Ph.D., EditorClare Baltazar, Ph.D.; Ireana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

MedicinePaulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.S

Vol. 98 No. 1 March 1969

National Science Development Board

Juan S. Salcedo, Jr., M.S., M.D.,ChairmanDiminador O. Reyes.,Ll. B.,

Officer-in-Charge, Office of Vice Chairman and Executive Director

Members of the Board

Pedro Afable, B.S.C.E. George T. Marcelo, B.S.B.A.Constacio M. Ancheta, Ph.D. Augusto L. Tenmatay, Ph.D.Jose R. Velasco, Ph.D.

National Institute of Science and Technology

Jose R. Velasco Ph.D., CommisionerFlaviano M. Yenko, A.B., B.S., Deputy Commisioner

Agricultural Research CenterClare R. Baltazar, Ph.D.

Director

Biological Research CenterLuz Baens-Arcega, M.S.

Director

Food & Nutrition Research CenterConrado R. Pascual, M.D., M.P.H.

Director

Industrial Research CenterFelife Ll. Santillan, B.S.M.E.

Director

Medical Research CenterRogelio N. Relova, M.D.

Director

Tests & Standards LaboratoriesJose P. Planas, B.S., Chem. Eng.

Acting Chief

The Philippine Journal of Science

Published quarterly by the National Institute of Science and Technology(Formely Bureau of Science), P.O. Box 774, Manila, Philippines

Carmen Ll. Intengan, Ph.D., EditorClare Baltazar, Ph.D.; Ireana R.F. Cruz, A.M.; Guillermina Mañalac, M.S., Associate Editor

Angel Y. Lira, B.S.E., Managing Editor

Contributing Editor

AgricultureAnacleto B. Coronel, D.V.Faustino S. Orillo, Ph.D.Antonio Pizarro, Ph.D.

AnthropologyAlfredo E. Evangelista, M.A.Robert B. Fox, Ph.D.F.Landa Jocano, Ph.D.E. Arsenio E. Manuel, M.A.

BotanyDemetrio R. Mendoza, M.S.Jose Vera Santos, Ph.D.Gregorio Velasquez, Ph.D.

ChemistryAlfredo C. Santos, Ph.D.Augusto L. Tenmatay, Ph.D.

NutritionLeon G. Alejo, B.S.Josefina B. Jayme, M.D.Sonia Y. De Leon, Ph.D.Luz U. Oñate, Ph.D.

GeologyArturo Alcaraz, M.S.Cecar B. Ibañez, M.S.Mateo H. Tupaz, Ph.D.Elpidio C. Vera, M.S.

Medicine

Paulo C. Campos, M.D.Conrado S. Dayrit, M.D.Rogelio N. Relova, M.D.Victor Valenzuela, M.D.

MicrobiologyMacario Palo, B.S.A.

Nuclear SciencePedro G. Afable, B.S.C.E.Ramon Samaniego, Ph.D.Getulio B. Viado, Ph.D.

ZoologyNelia P. Salazar, M.S.Leopoldo B. Uichanco, D.Sc.Agustin F. Umali, B.