560 BA CTERIOLOG Y. 



This group comprises the " septicaemias," and of them 

 the disease of animals knowh~as anthrax represents a 

 type of the condition. If the cadaver of an animal 

 dead of anthrax be examined by bacteriological methods, 

 there will be discovered present in all the organs 

 and tissues an organism, a bacterium, of definite form 

 and biological characteristics; and if the organs, and 

 tissues generally, be subjected to microscopic examina- 

 tion this same organism will be found and always 

 located within the capillaries. At many points it will 

 be seen crowded in the capillaries in such numbers as 

 almost, if not quite, to burst them, and very commonly 

 their lumen for a considerable extent is entirely occluded 

 by the growing bacteria. In such a case as this we might 

 be tempted to conclude that death had resulted from 

 mechanical interference with the capillary circulation. 

 Suppose, however, we subject the cultures obtained from 

 this animal to conditions, either chemical or thermal, 

 that are not particularly favorable to their normal devel- 

 opment, and from time to time inoculate susceptible 

 animals with the cultures so treated. The result will be 

 that, as we continue to expose our cultures to unfavorable 

 surroundings, the period of time that is required for 

 them to cause the death of animals will, in some cases, 

 gradually become extended, until finally death will not 

 ensue at all after inoculation. If, as these animals die, 

 a careful record of the conditions found at autopsy be 

 kept and compared, it will ultimately be noticed that 

 the animals that die at a longer time after inoculation 

 present conditions more or less at variance with those 

 seen in the original animal that died more quickly after 

 having been inoculated with the normal organism. These 

 differences usually consist in a diminution of the num- 



