I9i i.] 



The " Long Lactic Bacteria. 



3i3 



forms more commonly associated with the lactobacilli. It 

 would seem that the form of the colony is in some respect 

 determined by the form of the organism, and that this in 

 turn is dependent upon the conditions of growth. Thus the 

 more filamentous and spreading colonies were found to 

 contain lactobacilli of the longer forms, and vice-versa. 



It would seem, therefore, that micro-organisms of the lacto- 

 bacilli type are widely distributed in nature; that they occur 

 normally almost everywhere where mixed bacteria are 

 generally found, as in soil, air, water, foods of different kinds, 

 milk, and other dairy products, in the alimentary tracts of 

 human beings and animals, in human and animal fasces, &c. ; 

 that the natural habitat is not, as is commonly supposed, milk, 

 but more especially the intestines of animals. They find there 

 exactly the conditions to which they have become adapted, 

 i.e., a comparatively high temperature, diminished air 

 supply, and association with other types of organisms, par- 

 ticularly yeasts. But the intestines of an animal consuming 

 milk are, no doubt, a better breeding-ground for them than 

 those of an animal which does not partake of milk. This is 

 borne out. by the greater numbers which are found in the 

 fasces of infants and young animals on a milk diet. It 

 is interesting to note in this connection that soured milk 

 beverages have in olden times been prepared from goat's 

 milk by the addition of pieces of calf's stomach. The lacto- 

 bacilli, however, are present normally in numbers also in the 

 mouths of older persons and animals, and are probably in no 

 case entirely absent from the intestines. 



The presence of such micro-organisms in dairy produce 

 has undoubtedly a practical significance of great importance, 

 but time has not yet permitted further investigation into 

 this matter. The Cheddar cheese examined was a well- 

 matured, first-class Scots Cheddar of superior flavour and 

 general characters, and it is worthy of note that the lacto- 

 bacilli were present in great numbers, in large colonies, and 

 were by far the most numerous of the different forms of 

 bacteria present. This was confirmed by direct microscopic 

 examination. It would seem that the conditions present in 

 a comparatively large Cheddar cheese during ripening — prac- 

 tically anaerobic conditions — are favourable to the growth of, 



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