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262 ABSTRACTS AND REPORTS.
The above facts suggest a method of preventing the frauds which have now become so frequent in commerce and on the Contmental frontiers.
If a veterinary surgeon suspects that a particular animal has been given a dose of tuberculin with the object of defeating the tuberculin test, he should proceed as follows :-
About five or six o'clock in the morning a dose of tuberculin about double that usually employed should be injected.
The temperature should be taken every two hours from the time of injection up to the fourteenth or fifteenth hour.
The intensity of the reaction is indicated by the difference between the temperature at the moment of injection and the highest temperature shown during the following hours.
Any animal which gives a reaction of 1'5 0 C. must be regarded as tuberculous. A reaction of between 0'8'0 C. and I'S o C. should arouse suspicion.
Under no circumstances, however, should the test be made if the animal's temperature is already as high as 39 0 C. The animals should not be allowed to drink during the hour immediately preceding the taking of the temperature. (H. Vallee, RezJ. Gen. dc MM. Vet., No. 40, 15th August 19°4, page 161.)
THE ULTRA-MICROSCOPE.
HOLMHOLTZ and Abbe stated that, theoretically, the smallest object visible under a dry lens must be at least ;ri01}th of a millimetre in diameter, and in the case of an immersion lens at least -:nfooth of a millimetre. Siedontopf and Szigmondi, however, in the last volume of Poggendorf's Annals, describe a recently-invented microscope which they term the ultra-microscope. This instrument renders it possible to distinguish surfaces as small as oneT.1}ov'"ll"ll"llths of a square millimetre, or circles with a radius of T,OO~,"ll"ll"ll ths of a millimetre. The ultra-microscope furthermore has the extremely valuable property of facilitating the strongest possible illumination of the object, and thus rendering visible its special peculiarities.
Experiments undertaken in Zeiss' Laboratory in J ena with this instrument have already given astonishing results.
The guiding principle underlying the new method consists in an intense focal latcral Illumination, in consequence of which the particles under the microscope reflect the light which falls upon them, and appear self-luminous.
The full significance of the discovery cannot at present be appreciated, but it promises to be of great value for scientific and technical work. (Kosmos, 1904, Vol. I., Part I.)
THE INFECTIOUS CHARACTER OF ANlEMIA IN THE HORSE.
AT the present time a very interesting disease of the horse occurs throughout the entire valley of the Meuse, in the neighbouring Departments, and in Normandy. Its principal signs are those of grave progressive an~mia, and it usually ends in the death of the patient. This disease annually kills a large number of horses.
Whilst some authors regard it as due to faulty or insufficient feeding and to bad sanitary conditions, others believe it to be verminous or microbic in character.
As early as 1859 Anginiard reported cases of the transferencc of an~mia from horse to horse. His statements were confirmed by Ledru, and more recently by Mutelet and Roger (19°4). Nevertheless, in 185 r Delafond was un-
