60 



Scientific Proceedings (125) 



25 (1985) 



Studies on anthrax infection. 

 By W. L. HOLMAN 



[From the Department of Bacteriology and Experimental Path- 

 ology, Stanford University, San Francisco, California] 



The unsettled problems of infection with B. anthracis are very 

 many. Besredka has recently declared his belief that the 

 cutaneous is the only route of infection. Intestinal anthrax is 

 the commonest form in which the natural disease appears to be 

 found. The question has been raised whether there is such an 

 infection. The opposing view is that the findings and symptoms 

 in the intestines are only part of a general infection and that the 

 portal of entry is in the skin, usually about the mouth and nose, 

 and the local reaction, if any, is overlooked. In carrying out 

 some experiments to cover some of the doubtful points we under- 

 took the feeding of guinea pigs, taking particular care not to con- 

 taminate the mouth cavity. The technic used by previous work- 

 ers did not seem satisfactory so a simple method was tried which 

 protected against these possible contaminations. Small gelatine 

 capsules were filled with the culture to be used, the mouth was 

 opened and the capsules placed in the back of the throat. The 

 animal swallowed them promptly. A guinea pig was fed in this 

 way with a virulent culture rich in spores and a daily culture of 

 the feces was made in agar after heating to 75°C for 15 minutes. 

 A fecal pellet was emulsified in 10 c.c. of saline and 1 c.c. was 

 used for the plate. The colony characteristic of B. anthracis is 

 easily recognized but isolations were made each day and tested 

 on fresh animals. In this way we found virulent anthrax 

 spores in the feces up to the seventh day. Two weeks after the 

 feeding the animal was given a subcutaneous dose and died of 

 anthrax. A second pig was fed in the same way and positive 

 fecal cultures were obtained up to the fifth day. An accident 

 resulted in this animal's death on the eighth day but no micro- 

 scopic or cultural evidence of anthrax could be found. Four 

 guinea pigs fed in the same way were studied up to the twenty- 

 ninth day when they were killed by a subcutaneous route injec- 

 tion. These animals showed anthrax spores up to the tenth day 



