528 BACTERIA IX INFECTIOUS DISEASES NOT PROVED 



streptococcus is commonly found which appears to be identical with Strep- 

 tococcus pyogenes; and in the secondary affections which occur in the 

 course of this disease or during 1 convalescence, when suppuration occurs, one 

 or the other of the common pyogenic micrococci is usually found and is 

 doubtless the cause of the local inflammatory process. (See Otitis media, 

 page 525.) 



SYPHILIS. 



The etiology of syphilis has not been determined by the researches of 

 bacteriologists. For an account of the microorganisms which have been en- 

 countered in syphilitic lesions the reader is referred to the article on the 

 Bacillus of Lustgarten (No. 55). 



"TEXAS FEVER" OF CATTLE. 



Billings (1888) has announced the discovery of a bacillus in the blood of 

 cattle suffering from Texas fever, which he supposes to be the cause of this 

 disease, but the investigations of other bacteriologists have failed to confirm 

 the alleged discovery. It appears probable that a mistake in diagnosis was 

 made, and that the disease studied by Billings was an infectious form of 

 septicaemia in cattle similar to the Rinderseuche of German authors. The 

 microorganism which he has described as coming from the blood of the in- 

 fected animals resembles in its morphology Bacillus septicaemias hsemor- 

 rhagicee (No. 61), and, if not identical with this widely distributed species, 

 appears to be very nearly related to it. 



TYPHUS FEVER. 



The etiology of typhus fever has not been determined in a definite man- 

 ner. Hlava (1888) has described a " strep tobacillus " which he supposes to 

 be concerned in the etiology of this extremely contagious disease ; but it has 

 been shown by other investigators that this bacillus is not constantly present, 

 and there is no satisfactory evidence that it is the specific infectious agent. 

 Thoinot and Calmette encountered the streptobacillus of Hlava and various 

 other microorganisms in a certain proportion of the cases examined by them ; 

 but no one of these was constantly present. "An interesting organism," 

 which they did not succeed in cultivating, was found in the blood of all 

 cases examined by the investigators last mentioned. 



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 vai'ious microorganisms have been isolated from vac- 

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

 pathogenic power of unfiltered lymph from the same source. The experi- 

 ments of Carstens 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 experiments show that various disinfecting agents tested chlo- 

 rine, 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 virulence depends upon the presence of a living microorgan- 

 ism, however probable this appears, for certain toxalbumins are likewise 



