EXPERIMENT STATION BULLETINS. 217 



Although it was not our aim to work out in sufficient detail to establish 

 identity, for this would require months with each species, it was our 

 lot to study these bacteria isolated, sufficiently to give them identities 

 of their own. It was exceedingly trying to accomplish this, for where 

 there are two or three persistent differential characteristics prevailing 

 between species, and when all other characteristics are in common, the 

 task is important and very complicated. 



It has been the growing belief of some workers that where species 

 are practically identical, with the exception of two or three character- 

 istics, they could perhaps be brought under a single species, if the proper 

 conditions were obtained. There is good ground for this opinion which 

 need not be discussed in this connection. 



In our work all the different species were studied side by side under the 

 same conditions and cultivated upon the same media so far as it was 

 practicable. If we were to give the history of each showing a single 

 difference and even more, our number of species would be greatly 

 increased, but we have classified together those wbich seemed closely 

 allied, and could reduce the number still more, but it would probably 

 be to the detriment of our work. Our fear is, we have now overlooked 

 some interesting characteristics because of our desire to reduce the 

 number of species. 



We could discuss the relation of some of these species to- the hay 

 bacillus, the potato bacillus and others, but because of the indefiniteness 

 of lines of distinction, we must refrain from making any suggestions. 

 The limited histories must convey the importance of the bacteria and the 

 information where they may belong. 



Of the 39 varieties isolated and studied together the histories of only 

 ID varieties will be given, since we think so many of them are near 

 enough alike, but not exactly the same, to be classified together. After 

 the histories have been given of these 19, we shall be inclined to suggest 

 the grouping of others. 



The grouping of these bacteria may be represented as follows: 



Let the number stand for the laboratory number of the micro-organism 

 and the letter, the sample from which the micro-organism was taken. 



Numbers 3, 6, 9, and 12 do not come from any of the samples listed, 

 yet they were taken from Pasteurized milk. 



3— . 97— Y. 



6— , 12— , 122— P, 123—0, 124— N, 125— Q. 



9— , 16— B, 21— C. 



29— E. 



30— F. 



32— H, 40— Z, 82— T, S6— W. 



38—1. 



43— J. 



44— K. 



45— M. 



46— M. 



48— L, 37— G, 64— P, 65— Q, 73— R, 77— S, 81— T. 



60— O. 



62— P, 57—0. 



107— F. 



28 



