RopiNKSs IN Milk and Cream. 399 



except at the moment the samples were drawn. The wide mouth 

 of the bottle offered considerable opportunity for the entrance of 

 dust particles which might convey the bacteria had the particular 

 species in question been adhering to the udder. The twelve 

 samples were kept cool but none became viscid. 



All other samples were drawn into test tubes the mouths of 

 which presented a smaller area for the reception of dust. The 

 tubes had been previousl}^ plugged with cotton and heated, ren- 

 dering them absolutely sterile. At one milking period two sam- 

 ples were taken from each cow. One was from the first milk 

 drawn and the other from the strippings. Two more samples 

 were taken from each cow on different days. In every case they 

 were kept at a temperature of about 12° C, none of them becom- 

 ing viscid. 



Cultures were made from the milk of each one of the cows 

 on two different days, the bacteria present in the milk of each 

 cow being thus obtained in pure culture. From the first twelve 

 samples, there were obtained five apparently different species 

 none of which when grown in sterile milk brought about the 

 viscid condition. None of the species at all resembled the organ- 

 ism sought. In like manner a second series of cultures was made 

 from the milk of each of the cows with similar negative results. 

 During the period that the cultures were being made from the 

 milk, the ropy milk was constantly present in the creamery. The 

 evidence from these experiments leads to the conclusion that the 

 various species of bacteria which are always found in freshly 

 drawn milk did not, at that particular time at least, contain 

 among them the species capable of rendering the milk viscid. 

 Bacillus ladis viscosus itself furnishes evidence in support of the 

 conclusion that its natural habitat is not the ducts of the udder 

 as is true of many of the bacteria found in freshly drawn milk. 

 This microorganism does not grow so luxuriantly at the temper- 

 ature of the cow's body, 37.5° C, approximately, as it does at a 

 lower temperature. Such would probably not be the case if the 

 organism w^ere accustomed to living in the udder. 



In addition to examining the milk samples collected, a bacteri- 

 ologic examination was also made of those substances which 

 might harbor the obnoxious organism such as stable dust, par- 



