32 Dairy Bacteriology. 



contains, as a rule, many more organisms per cubic centi- 

 meter than that removed later. Not infrequently thou- 

 sands of organisms per cubic centimeter may be found 

 in the first streams while the middle milk, or strippings, 

 will contain much smaller numbers. 



Distribution and nature of bacteria in udder. If the 

 udder itself is carefully examined as to its bacterial con- 

 tent, it appears that the majority of organisms found 

 is confined to the lower portion of this organ, in the teat, 

 milk-cistern and large milk-ducts; while bacteria occur 

 in contact with the secreting tissue, they are relatively 

 less abundant. This would seem to indicate that the 

 more probable mode of infection is through the open 

 teat. 



While there is no constant type of bacteria found in 

 the fore-milk, yet it is noteworthy that nearly all ob- 

 servers agree that the organisms most commonly found 

 are not usually the acid-producing, or gas-generating 

 type, so abundant on the skin or hairy coat of the udder 

 and which predominate in ordinary milks. Coccus 

 forms, belonging to both liquefying and non-liquefying 

 types are most generally present. Many of these pro- 

 duce acid slowly and in small quantities. 



The bacteria coming from the interior of the udder 

 are of small practical significance since they do not grow 

 rapidly at the temperatures at which milk is stored. If 

 the milk is protected from contamination from other 

 sources, the bacteria from the udder will ultimately 

 cause it to spoil, but under ordinary conditions other 

 forms are present in such greater numbers, and grow 

 so much more rapidly in milk, that the udder forms 

 have small opportunity to exert any effect. 



It is interesting to note that the bacteria found in the 



