94 THE GROUSE DISEASE chap. 



difference, however, is shown in the rate of growth : 

 the colonies of the fowl -cholera bacillus grow con- 

 spicuously slower and remain smaller than those of 

 the fowl - enteritis bacillus. I have repeatedly had 

 occasion to make comparative experiments ; in this I 

 was ably assisted by Dr. Wood, of Melbourne, while 

 working in my laboratory : cultivations of the fowl- 

 cholera bacillus and of the fowl-enteritis bacillus were 

 made at the same time under the same conditions in 

 the same stock of nutrient gelatine, kept then under 

 precisely the same conditions, and always, without ex- 

 ception, the differences described above in the aspect, 

 and particularly the rate of growth, of the two microbes 

 were conspicuous and constant. The time at which the 

 colonies of the fowl - enteritis bacillus appeared, and 

 the rate with which they grew afterwards, the first 

 much shorter, the latter very much greater, were 

 appreciably different from those of the colonies of the 

 fowl-cholera bacillus. 



In sub-cultures in gelatine, in streak and stab, the 

 growth is distinct even during the second day : in 

 the streak culture a greyish-white flat band appears, 

 which gradually broadens during the following days ; 

 its margin is irregularly knobbed and sinuous. After 

 about two weeks the band is 3-5 millimetres broad, 

 but it remains flat ; in reflected light it looks whitish, in 

 transmitted light, light brown. In stab culture, during 



