Contamination of Milk. 33 



udder are similar to those that seem to be most abun- 

 dant in such glandular tissues as the liver and spleen. 

 This fact increases the probability that these compar- 

 atively inert coccus forms of the udder may originate 

 directly from the blood stream. The organisms that 

 normally are found in the udder exert no harmful ef- 

 fects on the gland. It might be thought that due to the 

 presence of abundant food and a favorable temperature 

 that growth would be abundant, but such is not the 

 case. At times the udder may be invaded by forms that 

 are not held in check by the natural factors and an in- 

 flammation of the udder is likely to result. 



Germicidal property of milk. It has been claimed 

 that freshly drawn milk, like other body fluids, possesses 

 germicidal properties, i. e., the power of destroying bac- 

 teria with which it may be brought in contact. If milk 

 is carefully examined bacteriologically, hour by hour, 

 after it is withdrawn from the udder, it will generally 

 be found that there is at first not only no increase in 

 number of organisms during a longer or shorter period 

 when it is kept at temperatures varying from 40 to 70 

 F., but that an actual reduction not infrequently takes 

 place. When cultures of bacteria, such as B. prodigi- 

 osus, a red organism, lactic acid organisms, and even the 

 yellow, liquefying coccus, so commonly found in the 

 fore-milk, are artificially introduced into the udder, it 

 has been found that no growth occurs and that in the 

 course of a few days the introduced organisms actually 

 disappear. Whether this failure to colonize can be re- 

 garded as evidence of a germicidal property or not is 

 questionable. In fact, this question is a matter of but 

 little practical importance in the handling of milk since, 

 under the best of conditions, the keeping quality of the 

 3 



