IMMQNITY AGAINST MICROBMS. 435 



two days previously with spores of anthrax in the same eye. 

 Before introducing the thread it was ascertained that the 

 aqueous humour of the eye contained a considerable number 

 of leucocytes, but no free bacilli ; the day after, on withdraw- 

 ing the thread, it was seen that a certain number of spores had 

 grown into bacilli composed of several (as many as six) seg- 

 ments. In another similar experiment the piece of silk thread 

 was introduced five days after the first inoculation, and at a 

 time when the bacilli had already entirely disappeared. Twenty- 

 four hours afterwards newly grown bacilli, showing as many 

 as seven segments, were found in the exudation from the eye. 

 The bacilli took a dark blue colour with methylene-blue, and 

 were quite normal. 



Repeated subcutaneous inoculations into pigeons which had 

 already recovered from one attack of anthrax no longer gave 

 rise to serious symptoms. Nevertheless the bacilli introduced 

 in the state of spores fixed on silk threads grew more or less 

 abundantly. 



Four hours only after the subcutaneous inoculation of very 

 virulent anthrax into pigeons a marked emigration of micro- 

 phages took place at the point of inoculation, and some of 

 these contained one or more and as many as nine bacilli. 



After a time the inflammation increased, and a larger number 

 of phagocytes — micro- and macro-phages — accumulated at the 

 point of inoculation. Many phagocytes, especially those which 

 were crammed with bacilli, burst very easily, allowing their 

 contents, including micro-organisms in every stage of de- 

 generation, to escape. This bursting took place not as a 

 consequence of the mode of preparation, but also in the living 

 animal — as was proved by the degenerated form of some 

 phagocytes containing bacilli. 



In pigeons which recovered from the disease the larger num- 

 ber of the bacilli were found in the interior of the phagocytes, 

 whilst in the birds which perished the majority of microbes lay 

 outside the cells, although in all, the amoeboid cells devoured a 

 large number of micro-organisms. So full were the micropiiages 

 sometimes that their nuclei could hardly be made out, and when 



