60 EXPERIMENTAL DAIRY BACTERIOLOGY 



A sample of the foremilk, the first 10-15 cc. of a single 

 quarter, should be drawn directly into a sterile, wide-mouthed 

 bottle or flask, as well as a sample of the strippings from the 

 same quarter. A sample should also be taken from the pail 

 after the milking of the individual animal is completed. 

 Quantitative analyses are to be made in the usual way. The 

 various samples should be kept at room temperature and 

 frequent observations made, in order to determine the keep- 

 ing quality and the nature and flavor of the curdled milk. 



Exercise. Each student will collect samples of foremilk and strip- 

 pings from one quarter of each of two cows, and also from the pail 

 at the end of the milking of each animal, and examine the samples 

 quantitatively. 



Contamination from utensils. The amount of contamina- 

 tion which the milk receives from the various utensils used 

 in the handling depends entirely upon the cleanliness of the 

 same. The degree of cleanliness of these utensils turns not 

 only on the manner in which they have been washed, but 

 upon the construction and condition of the utensil. A milk 

 pail pressed from a single sheet of metal, and well tinned, 

 is easily cleaned, for it has no crevices and joints into which 

 the milk can penetrate, and from which it is impossible to 

 remove it. A pail constructed in the ordinary way, with 

 folded seams, is less easy to keep in a condition of bacterio- 

 logical cleanliness. With the increased complexity of con- 

 struction it becomes more and more difficult to maintain any 

 utensil in a sanitary condition. 



On the farm most of the utensils are of such a nature as 

 to be cleaned easily, but in the creamery, cheese factory, etc., 

 where cream separators, pasteurizers, and numerous pipes are 

 made use of in handling the milk, the difficulty is increased. 

 On the farm the most difficult utensils to keep clean are the 



