191 1.] The "Long Lactic Bacteria." 



309 



and anaerobic conditions. They are all non-motile and non- 

 sporogenous. They have a tendency to chain formation and 

 to show involution forms. The cell body is often seen to 

 contain a varying number of round to oval bodies or granules. 

 The colonies in whey agar vary in appearance from a round 

 to an irregular, curled, filamentous structure, with periphery 

 mostly filamentous and often streaming, but in a few cases 

 smooth and even. It is believed that milk is the natural 

 habitat of the bacteria of this particular group, and that 

 growth in the human intestines follows only upon internal 

 administration by consuming fermented milks. 



According to Hastings and Hammer,* bacteria of this type 

 form a supposedly new group of organisms. As far as they 

 are aware, no one has supposed that these organisms are 

 commonly present in milk. While Freudenreich has found 

 them widely distributed in Swiss milk, Swiss cheese, and 

 whey rennet, they are not aware that they have been found 

 elsewhere in market milk. 



By microscopic examination of milk incubated in stoppered 

 bottles at 37 0 C. for several days until a higher degree of 

 acidity was obtained than was sufficient to suppress the 

 bacteria of the common lactic streptococci type, these in- 

 vestigators found long slender cells appearing, which 

 increased in numbers with increasing acidity until they were 

 the predominant form. They found isolation of such long 

 forms difficult, and possible only by making repeated inocu- 

 lations from milk with a high acidity. By such methods 

 they found the lactobacilli type of bacteria to be widely 

 distributed in American milk and in American butter and 

 cheese. 



They point out, however, that in Conn's latest classifica- 

 tion of dairy bacteria no such organisms are described, and 

 conclude that this class of bacteria, though undoubtedly 

 characteristic of milk, has eluded the search of American 

 bacteriologists, and to a great extent of European bacterio- 

 logists also, because the methods employed have not been 

 such as to attract attention to them; and that nothing is 

 definitely known as to the natural habitat of the organisms. 

 Thg believe that the significance of this group of bacteria 



* Centralblatt fiLr Bakter., Bd. 25, 1909. 



