VIII A PATHOGENIC BACILLUS 75 



the mixture, one died on the fifth day, the other 

 survived. In series three, both mice done with the 

 culture of maHgnant oedema were found dead on the 

 second day with abundant bacilH of maHgnant oedema 

 in the blood ; both mice done with the culture of the 

 grouse bacillus were found dead on the second day 

 with abundant bacilli of the grouse disease in the 

 blood ; and both mice done with the mixture were 

 alive and well on the seventh day. Now in this last 

 series the amount of the mixture injected in the last 

 two mice was double the amount of the culture of 

 malignant oedema and of grouse separately, and al- 

 though the two mice that were inoculated with the 

 same amount of malignant oedema alone, as also the 

 two mice inoculated with the same amount of grouse 

 culture alone, succumbed, yet the two mice inoculated 

 with the mixture, that is, with double the amount, 

 survived. Clearly there is then a decided antagonism 

 within the body of the mouse between the two species, 

 by which the action of the one is neutralised by that 

 of the other. If the two species were the same, then 

 the two mice done with the mixture, having received 

 a double dose, ought to have succumbed so much 

 more readily, whereas on the contrary they remained 

 alive ; it follows from this that the two microbes are 

 two totally different species. This conclusion must, 

 therefore, remove all doubt as to any close relation 



