32 Dairy Bacteriology. 



a characteristic not usually associated with the lactic acid 

 class. 



Bolley 1 in thirty experiments found twelve out of six- 

 teen species to belong to the lactic acid class. In no 

 case were gas- generating species present. This fact is 

 important in the selection of a milk from a single animal 

 for the cultivation of a starter. 



This condition represents the milk of perfectly healthy 

 animals; where the udder is diseased, as in the case of 

 infectious garget or inflammation, bacteria may be pres- 

 ent in much larger numbers and affect the milk seriously 

 for food purposes. 



Not all species seem to be able to maintain themselves 

 in the udder even if they should be introduced. Dinwid- 

 die 2 injected into the milk cistern a lactic acid producing 

 facultative anaerobe that grew luxuriantly at 99 F. An 

 examination of the milk several times afterwards failed 

 to show the presence of this organism in any case, 

 although other species were isolated. 



38. Dirt from animal. By many it is believed that 

 much of the germ life that gets into the milk comes from 

 the food of the animal. For this reason fermenting 

 food- stuffs of any kind are regarded as unfit for use. 

 While material of this class is not a suitable nutrient for 

 any animal, the danger to the milk is not due to the bac- 

 teria ingested with the food, but to a large extent to those 

 that adhere to the animal's coat, and subsequently fall 

 into the milk. Of course the udder may be infected if 

 the animal is diseased as in inflammation (mammitis), 3 



1 Assoc. Ag. Coll. and Expt. Stat.,1895, also Cent. f. Bakt. II Abt. 

 1: 795, 1895. 



Second article, Bull. No. 21, N. D. Expt. Station. 



2 Dinwiddie, Ark Expt. Stat, Bull. 45, p. 57. 



3 Guillebeau, Landw. Jahr. d. Schweiz, 1892, p. 27. 



