28 Dairy Bacteriology. 



of sterile water, using a sterile swab to remove all dirt. 

 This process was repeated with two otlrr rinse waters of 

 the same volume, and from each of these plates were made 

 with following results: 



No. bacteria in different washings. Total No. 



bacteria. 

 9,299,000 

 361,400 

 1,851,400 



Infection of udder cavity. While it may be true that 

 milk as secreted in the glandular tissue of a healthy ani- 

 mal may be practically iree from bacteria, yet it does not 

 follow that it contains no microbes when first drawn. In- 

 deed, a bacterial examination of the first few streams taken 

 from each teat will invariably show a relatively high germ 

 content; much higher, in fact, than that which is subse- 

 quently withdrawn. The reason for this is evident when 

 the structure of the udder and its relation to the exte- 

 rior is noted (Fig. 8). The udder is composed of secreting 

 tissue (gland cells), held in place by fibrous connective tis- 

 sue. Ramifying throughout this glandular structure are 

 numerous channels (milk sinuses) that serve to convey the 

 milk from the cells where it is produced into the milk cis- 

 tern, a common receptacle just above the teat. This cavity 

 is connected with the exterior through the milk duct in the 

 teat, which is closed more or less tightly by the circular 

 sphincter muscles, thus preventing the milk from flowing 

 out. 



According to the best authorities, the fat globules are 

 elaborated very largely during the actual manipulation of 

 the udder in milking, yet there is always a small residual 

 amount of milk that is not removed even by " clean" milk- 

 ers. 



