PRESENCE OF BACTERIA 



63 



coal gas, or prussic acid. The abdomen was 

 immediately incised, and the appendix plunged 

 in absolute alcohol or in 10 per cent, formalin 

 in normal saline. Thus there could be no ques- 

 tion of a post-mortem penetration of the tissues 

 by the bacilli. I first found the bacilli in the lymph 

 tissues by overstaining with cold carbol-fuchsin for 



From a photograph of bacilli in the lymphoid tissue of a healthy 

 rabbit's Peyer's patch. (Eosin-Gram stain; 1/12 in. objective.) 



twenty-four hours and then decolourising with oil of 

 cloves a varying number of hours — examining the sec- 

 tion from time to time. But I soon found a better 

 way which had also been used by Buffer and his pre- 

 decessors. The bacteria in the rabbit's caecum are for 

 the most part large in size and strongly Gram-positive. 

 They are, possibly, anaerobic, for Dr. Macfarlane was 

 unable to cultivate them for me on aerobic media when 



