ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
223 
again capable of killing an adult guinea-pig and even a rabbit, but 
ineffective against ruminants or horses, though highly vaccinal towards 
them. 
(3) The bacillus whose revivification has been rendered complete, 
that is, is mortal to the sheep ; this type is probably still only vaccinal 
to the cow or the horse. 
It will be remembered that the non-virulent bacilli were obtained by 
cultivations brought into contact with compressed oxygen. To restore 
the virulence it is necessary to add blood to the cultivation in contact 
with greatly rarefied air. If the blood be that of a guinea-pig the 
bacilli produced will kill mice and just-bom guinea-pigs, and, later on, 
adult guinea-pigs and rabbits. To make these bacilli capable of killing 
sheep, the blood of a sheep must be added, and the spores of cultivations 
thus prepared are mortal to small mminants. 
Metabolism of Micro-organisms.^ — Dr. G. Strazza has made some 
experiments with the object of ascertaining to what extent micro-organisms 
cause metabolism of the nutrient medium in which they are cultivated. 
The result of his experiments is that a distinct loss of weight can be 
demonstrated, but this loss is extremely small, and is represented in the 
second or third place of decimals. Secondly, that this loss of weight is 
accompanied by the production of carbonic acid. 
The micro-organism which was mostly used for these experiments 
w^as Micrococcus prodigiosus. In the first set all that was requisite was 
to weigh the tubes carefully before and after growth, and compare this 
loss with the loss of weight due to evaporation from an equal surface of 
gelatin. The next thing was to show that the loss was due to develop- 
ment of gas, and this was effected by inverting the inoculated test-tube 
over caustic potash, when it was found that the liquid ascended 5-10 mm. 
That the gas developed by the metabolism of the micro-organisms was 
carbonic acid was shown by its causing a precipitate with lime water. 
Action of the Gastric Juice on Pathogenic Microbes.f — MM. J. 
Strauss and E. Wurtz have examined the action of the gastric juice 
of the dog, man, and sheep on the bacilli of tubercle, anthrax, enteric 
fever, and cholera. The gastric secretion was placed in test-tubes, in- 
oculated with the microbes, and kept at a temperature of 38° C. After 
various periods of time inoculation experiments in guinea-pigs and 
rabbits showed that tubercle bacilli survived the action of the 
gastric juice up to six hours sufficiently well to produce a general 
tuberculosis. From 8-12 hours a tubercular abscess was formed at the 
inoculation site, and this quickly healed. After 18 hours the bacilli 
were either dead or had lost their virulence. Anthrax bacilli without 
spores were killed in 15-20 minutes, and the spores died after 30 minutes. 
Under similar conditions typhoid bacilli died in 2-3 hours, and cholera 
bacilli after 2 hours. 
Further experiments with hydrochloric acid in the proportion of 0 • 9, 
1*7, and 3 per thousand on anthrax, cholera, and typhoid bacilli gave 
similar results to those obtained with gastric juice. Hence the authors 
MT. Embryol. Instit. Univ. Wien, 1888, pp. 8-13. 
t Arch. Med. Exper. et d’Anat. Pathol., 1889, No. 3. Cf. Centralbl. f. Bakteriol. 
u. Parasitenk., vii. (1890) p. 39. 
