SEPTIC^MIA IN MICE. 



353 



to be even greater than in anthrax. In order to 

 infallibly bring about the death of one of these 

 little animals within the time stated, about fifty 

 hours, it is sufficient to pass the point of a 

 scalpel, which has been in contact with the in- 

 fected blood, over a small wound in the skin. 



Koch suspected that this great virulence was 

 due to the abundant presence of a micro-organism 

 in the infectious material, 

 but failed in his earlier ef- 

 forts to find this parasite in 

 septiccemic blood. This was 

 found, later, to be owing to 

 the minute size of the ba- 

 cilli to which the disease is 

 ascribed ; and by the use of 

 Abbe's condenser he was 

 able to demonstrate the 

 presence in large numbers 

 of the bacilli seen in Fig. 19, 

 which is copied from his work (I. c.). 



"The bacilli lie singly or in small groups between the 

 red blood corpuscles, and have a length of .8 to 1 p. 

 Their thickness, which cannot be measured accurately, 

 but only approximately estimated, is about .1 to .2 //,. 

 . . . One often sees the bacilli in septiesemic blood 

 attached to each other in pairs, either in straight lines 

 or forming an obtuse angle. Chains of three or four 

 bacilli also occur, but they are rare. . . . Without the 

 use of staining materials, the bacilli can only with 

 extreme difficulty be recognized in fresh blood, even 

 when one is familiar with their form ; and I have not 



23 



Fig. 19. 



White blood-corpuscles from one 

 of the veins of the diaphragm of 

 a septicaemic mouse. X 700. 



