616 BACTERIA IN INFECTIOUS DISEASES. 



cases out of six in which cultures were made from material obtained from 

 the spleen, post mortem, a very minute diplococcus developed, at 37 C. This 

 formed a grayish layer upon the surface of nutrient agar at the end of two 

 or three days. 



TUBERCULOSIS. 



The various forms of tubercular infection in man are due to a 

 single specific infectious agent Bacillus tuberculosis (No. 53). Tu- 

 berculosis in cattle is due to infection by the same bacillus. The 

 bacillus which produces tuberculosis in fowls closely resembles that 

 of human tuberculosis, but owing to slight differences is described 

 under a separate heading Bacillus tuberculosis gallinarum (No. 54). 



VARICELLA. 



Various microorganisms have been found in the contents of the vesicles 

 and pustules of varicella, but there is no evidence that any one of these bears 

 an etiological relation to this specific eruptive fever. 



VARIOLA AND VACCINIA. 



The etiology of small-pox still remains undetermined. The common pus 

 cocci and various other microorganisms are found in the characteristic pus- 

 tular eruption, and various microorganisms have been isolated from vaccine 

 vesicles ; but no one of these has been shown to possess the specific pathogenic 

 power of unfiltered lymph from the same source. The experiments of Cars- 

 tens and Coert show that the specific virulence of vaccine lymph is destroyed 

 by ten minutes' exposure to a temperature of 54 C. And the writer's experi- 

 ments show that various disinfecting agents tested chlorine, sulphur dioxide, 

 nitrous acid destroy the infective virulence of lymph dried upon ivory 

 points in about the same proportion as is required for the destruction of some 

 of the best-known pathogenic bacteria. But this does not prove that viru- 

 lence depends upon the presence of a living microrganism, however probable 

 this appears, for certain toxalbumins are likewise destroyed by a correspond- 

 ingly low temperature and by the action of various chemical disinfectants. 



Nikolsky (1892) obtained from the base of the pustules of small-pox a mo- 

 tile, liquefying, spore-producing bacillus which when introduced into ilie 

 peritoneal cavity of rabbits is said to have given rise to a pustular eruption ; 

 the bacillus was recovered in cultures from these pustules. Grigorijew 

 (1889) in three cases found a small bacillus, twice as long as thick, which 

 slowly liquefied gelatin, and did not coagulate milk. Besser (1893) givrs an 

 account of the microorganisms found in the pustules of variola and adds to 

 the list a bacillus found by himself in a single case. This does not grow in 

 gelatin at the room temperature and is more slender than the bacillus of 

 Grigoriew. 



The results of the researches of Martin (1891) have been reported by Ernst 

 (1893). He obtained various bacteria from the lymph of vat-cine vesicles, 

 and among these was a bacillus which he believed to be the specific infectious 

 agent. This he was able to cultivate upon the surface of sterilized blond 

 serum of the ox, at 37 C., and his cultures of the ninth generation are said 

 to have produced typical cow-pox when inoculated upon calves. He says : 

 4 'The material 'takes' with the same certainty as the lymph from the vesicle. 



