232 Bulletin 158. 



the cause for the variety of unpleasant taints and flavors detected 

 by cheesemakers and buyers. The cause for the considerable 

 number of taints however, needs further elucidation, but the 

 experience with this particular species of bacteria indicates that 

 our explanation may be found to be correct. Certainly, the 

 economic importance of these disagreeable taints and flavors 

 render a more thorough and general investigation into the causes 

 and means of prevention much to be desired. 



Summary. 



The results obtained in the investigation herein reported may 

 be summarized in the following statements : 



1. The " gassy " and tainted curds were caused by the action 

 of a certain species of bacteria which was present in the milk. 



2. This organism w^as introduced into the milk at the time of 

 milking. It came from the milk ducts of the teat or, perhaps, 

 from those of the udder. There seems to be no evidence that it 

 was carried into the milk with the particles of dust or bits of dirt 

 which invariabl}" fall into the pail unless special precautions are 

 taken to prevent their entrance. 



3. The organism is closely related to Bacillus coli commuyiis, 

 a species of bacteria commonly found in the intestinal tract. 



4. Positive evidence was not obtained to show that the 

 retained placentas, with their subsequent decomposition and dis- 

 charge, were the cause of the milk duct infection with the micro- 

 organism which produced the gas and taints in the curds. 



5. The wide distribution of this organism in the milk ducts 

 of the cattle, and its apparent absence or at least infrequency in 

 the dirt of the stable, indicates that the cattle had been exposed 

 in some way to this organism. It is very likely that the decom- 

 posing membranes might have been the channel through which 

 the infection took place. 



6. The milk duct infection of all of the cattle in the dairy 

 wnth this organism was made possible by the fact that the stable 

 w^as not thoroughly cleaned and disinfected as soon as the trouble 

 with the *' gassy " curds and taints began. 



7. Certain species of bacteria when once introduced into the 

 udder are able to remain there for a considerable length of time. 



