l82 



there, and since the normal temperature of a birds' 

 blood is something about 109° F., the heat is there 

 also — with a vengeance. 



Heat and moisture by themselves are not sufficient 

 to render the bacillus invariably pathogenic, because 

 so long as a strong a7id healthy bird is fed on simply 

 seed and water and sound greenstiiff \:i^ can swallow the 

 spores of the bacillus and even the bacillus itself (as 

 he must of necessity be constantly doing), without 

 any harm accruing to him. A cage and its appur- 

 tenances, unless they are frequently and periodically 

 boiled, swarm with septic bacilli, revelling in the 

 bird's excreta and in the inevitable slime in the 

 corners of the drinking glass ; but except in the very 

 rare instances of such a bird becoming debilitated by 

 some ordinary disease, or in the commoner one of his 

 being newly caught, nothing need happen to him. 

 He takes in the bacilli ; the digestive juices settle the 

 greater proportion of the unwelcome visitors ; and the 

 phagocytes account for any that migrate into the 

 blood stream. And happily this is what goes on from 

 day to da3\ 



An account in his own words of one of Dr. 

 Clarke's experiments will make the preceding plain : 

 " I got two .strong, healthy Canaries, A and B ; they 

 *' were fed on seed and water only. A's food and 

 *' water were freely contaminated with a culture of 

 "characteristic septic bacteria bred in putrid &%%. 

 " B's food and water were contaminated with the 

 " excrement of A. Neither bird showed the slightest 

 " ill effect and the excreta of both birds were almost 

 " entirely free from bacteria. After allowing sufficient 

 " time to elapse to make sure the birds were quite free 

 " from disease, the experiment was repeated, but both 

 " birds were given plenty of fresh hard boiled ^z%. 

 "Almost at once the excrement of both birds was 

 "found to be swarmins: with characteristic bacteria, 



