Gas and Taint in Cheese Curd. 229 



throughout the stable, and, coming in contact with the end of 

 the teats, this particular species found a suitable place for multi- 

 plying and from there grew up into the udder. The examination 

 of the milk from several animals in different dairies fails to show 

 a common invasion with this or similar organisms. A careful 

 comparison of the bacillus obtained with different cultures of 

 Bacillus coli comniiuiis, isolated from the intestines of cattle, 

 shows that there is an appreciable difference between the two 

 although not enough to place them in separate species. The 

 facts warrant us in supposing that this particular organism 

 possessed, to an unusual degree, power to invade the milk ducts 

 just as certain cultures of a species of pathogenic bacteria 

 possess more virulence than other cultures of the same species. 



It is unfortunate that an examination of the milk of each cow 

 was not made early in the course of the trouble. While it is not 

 demonstrated that this organism was present in the decomposing 

 uterine membranes, it has been shown that bacteria of this group 

 often get into the uterinecavity in cases of parturient difficulties. 

 It has also been pointed out that the colon bacteria, like certain 

 other organ isms, may have their properties modified when they are 

 grown under different conditions or environment. It would 

 probably have been possible, had the examinations been made at 

 the proper time, to have determined whether the organism in 

 question made its appearance simultaneously with the discharge 

 of the putrid placenta, and whether or not the cows thus affected 

 were the first to have had their milk contaminated with this 

 species. 



It has long been recognized that the species of bacteria in the 

 fore milk are modified largely by the conditions under which the 

 cattle are kept. When on green pasture with little or no oppor- 

 tunity to get into mud or filth, the number and species of bac- 

 teria in the milk are much smaller and different than they are 

 when the cows lie in filth}- yards or stables. 



It is important to bear in mind that when certain bacteria get 

 into the milk ducts of the teat, or possibly in those of the udder 

 itself, there is a tendency to become localized and to remain there 

 for a considerable time, while other species do not take readily 

 to this environment. In the examination of the fore milk from 



