226 Bulletin 158. 



very closely the one isolated from the "gassy " curd although 

 they approached it in some one or more of their properties. 

 After a careful but fruitless search in these substances for this 

 organism the conclusion seemed to be supported that this bacillus 

 was not widely disseminated at that time in the stable. This 

 suggested that the obnoxious organism got into the milk through 

 the teat infection rather than on the particles of dust which fall 

 into the milking utensils. A further argument for the teat 

 infection rests in the fact that after the stable was thoroughly 

 cleaned and disinfected, the trouble continued without immediate 

 abatement. Graduall}^ however, it began to disappear, and late 

 in the fall it had practically ceased. The constant cleansing 

 prevented reinfection so that when the teats happened to be 

 cleared of this organism they were not again infected with it. 



It has long been known that the fore milk when drawn under 

 aseptic precautions contains bacteria. Their presence is gener- 

 alh' supposed to be due to the infection with the bacteria which 

 chance to get upon the end of the teat, multiply there in the 

 remaining drop of milk and gradually grow up on the mucous 

 membrane of the milk duct from which the}^ are washed out dur- 

 ing the subsequent milking. The examinations made in the 

 present investigation suggested that the gas and taint producing 

 bacteria had, in addition to this temporary invasion, become 

 colonized in the udders of certain of the cows. This, however, 

 could not be positively determined. 



Although the present knowledge of the extent of the bacterial 

 invasion of the udder presumes that it is not extensive and under 

 normal conditions probably does not reach beyond the teats, it 

 seems difficult to explain the results obtained without presuming, 

 as did Gernhardt, that sometimes the bacteria grow up through 

 the teat and cistern into the ducts of the glandular tissue. A 

 few months after this investigation, we had the privilege of 

 examining bacteriologically the udders from several freshly 

 slaughtered milch cows and found that the mammary gland is, 

 sometimes at least under presumably normal conditions, invaded 

 with bacteria. This fact strengthens our belief that in the case 

 of the gas producing bacteria, they had invaded the udder itself 

 and become colonized there. As the results of the bacteriologic 



