194

a well-known physical law-will be distributed in

greater concentration at the interface in question, inthis case the bacterial envelope, than in the suspendingfluid. Dr. Rideal suggests that the self-lirnitation ofbacterial growth depends upon the production bybacteria of metabolic products, which have this effectupon the surface tension and thus become concen-

trated upon the bacterial surface ; these substances,being in their way excretory products, are unfavour-able to the organism’s growth and nutrition, whichfinally ceases to progress. Upon removal to freshmedium, the equilibrium is upset and the adsorbedsubstances are to some extent desorbed,allowing growthto occur again. Fresh bacteria can grow in the oldmedium for a short time because the concentrationof these substances in its bulk is not sufficiently highto be inhibitory. It is not possible to put this s

hypothesis to experimental proof by measurement ofthe interfacial tension between bacteria and medium, ’,but it is easy to measure the medium air interfacialtension which in many cases will probably have avalue relatively similar. It is found that with a rangeof antiseptics, from thymol to phenol, the effect uponthe surface tension is accurately correlated withantiseptic activity, which suggests the presence of anadsorption factor on these lines. The question of theselective adsorption of the various products presentedto bacteria is, in its ultimate analysis, a chemical one,depending upon the presence in the bacteria of reactivegroups capable of combining with those available inthe dissolved substances of the circumambient fluid.

CONJUNCTIVAL INFECTION WITH TUBERCLE.

IN 1913 A. Calmette and his fellow workers drewattention to the possibility of infecting guinea-pigswith tubercle bacilli by the conjunctival route, andit was thought that a clue had been found to thegenesis of the cervical adenitis of childhood. Thoughthe virus transmitted through the conjunctivas spreadto the cervical glands, the tracheo-bronchial glands,the lungs, and abdominal viscera, lesions at the levelof the eye itself were never observed. We alludedbriefly last week to similar investigations conductedby Prof. S. Lyle Cummins with results that did notin every respect tally with Calmette’s. Prof. Cumminsfound 1 that a definite local inflammatory reactionin the eye itself usually occurs but is very late inappearing. Of two guinea-pigs infected by the con-junctival route, one (No. 125) was a normal animal,and the other (No. 123) had been inoculated a monthearlier with tubercle bacilli of low virulence. In thisanimal acute conjunctivitis developed a day afterthe conjunctival instillation, whereas in the case ofNo. 125, the conjunctival did not become inflameduntil the third week after the instillation. It wouldseem that the rapid onset of acute conjunctivitis in theanimal already infected with tubercle bacilli of lowvirulence was due to an allergic state induced by theearlier infection. Comparisons made between theeffects of subcutaneous injection and conjunctivalinstillation of tubercle bacilli brought out one veryinteresting point. Among the guinea-pigs givensubcutaneous injections of varying quantities oftubercle bacilli, there was no appreciable difference inthe reaction, whether 2000 million or only 2000bacilli were injected. But when the bacilli were

introduced by the conjunctival route, the course ofthe disease varied according to the dose ; it wasrapid and acute when a concentrated emulsion oftubercle bacilli was instilled, and chronic whendilute instillations were given. These observationsgive support to the hypothesis that in the tuberculosisof man the massiveness of infection plays an importantpart. The condition of the child whose only apparentdefect consists of enlarged cervical glands may becompared with that of guinea-pig No. 125 which seemedto be in excellent general health six months after

conjunctival infection. When killed it was found tohave lesions strictly limited to the infected eye and

1 Tubercle, January, 1924.

the cervical glands, which were fibrotic and containedlimited areas of caseous degeneration. Prof. (’ummin5suggests that artificial per-conjunctival infectionshould help to elucidate many of the phenomena oftuberculous infection and resistance, although theconstant association of eye lesions with the cervicaladenitis in guinea-pigs indicates that the tuberculousprocesses in the guinea-pig and man are not strictlysimilar. And his suggestion is worth following up.

THE TREATMENT OF NEURO-SYPHILIS.

THE issue in the discussion before the MedicalSociety for the Study of Venereal Diseases, reportedin THE LANCET of last week, on the diagnosis andtreatment of neuro-syphilis, turned largely on thevalue of tests applied to the cerebro-spinal fluid as aguide to prognosis and treatment. Dr. GordonHolmes, who opened the discussion, contended thatthe diminution of the cell content often quoted asa sign of improvement might be due to repeatedlumbar puncture, since some of the cells in the lower-part of the cord are drawn off at each puncture, andthe proportion found in the later counts thus reduced.Dr. Holmes confessed to have made more than oneserious mistake through being guided by changes inthe cerebro-spinal fluid. As to treatment he main-tained firmly that the study of this fluid formed noreliable guide to the efficiency of treatment or prog-nosis in neuro-syphilis, except in interstitial syphilis.Colonel L. W. Harrison, as President of the Society,took up this point in a reasoned comment on Dr.Holmes’s opening address. He expressed himself asanxious to accept what he understood to be Dr.Holmes’s view that lumbar puncture was not so

necessary for the control of treatment of cases ofsyphilis as our American colleagues would have usbelieve. Many held that no case of syphilis couldbe considered to be properly managed unless thetreatment were controlled by examinations of thecerebro-spinal fluid, and this view entailed thedifficulty that, with all precautions, lumbar puncturewas apt to be followed by severe headache, whichraised great practical difficulties for the ordinarypatient. Perhaps the point raised by Dr. Holmes as tothe effect of intensive treatment on the developmentof the neuro-recidive might be cleared up by theexperience in treatment centres as to -the number ofcases of neuro-recidive which they have seen amongstsoldiers treated for syphilis during the war. Therewere approximately] ] 00.000 cases of syphilis treatedin military V.D. hospitals in that period, most ofthem by a short, rather intensive course. Throughthe medium of this Society, statistics on this pointmight be collected during the next few years frommedical officers of treatment centres, neurologists.and practitioners who had come across cases ofneuro-recidive amongst soldiers treated for syphilis inthe war years. Particulars of the actual treatmentadministered would be necessary, as well as of thenature of the present disease.

POST-OPERATIVE DENTAL TREATMENT OF

CLEFT PALATE.

A RECENT paper by Mr. A. T. Pitts on theOrthodontic Treatment of Cleft Palate Subsequent toOperation contains much information that will befound useful, not only by dentists but by surgeonsand general practitioners. Mr. Pitts thinks thatsome surgeons have not realised that the cooperationof the dentist is absolutely necessary to get the bestresults in the treatment of cleft palate, and there isdoubtless much truth in this contention. Surgeonswho are accustomed to operate much for this deformityknow how difficult it often is to get parents to seethe necessity for dental treatment and for trainingin articulation, in the case of children who have

1 British Dental Journal, Dec. 15th, 1923.