SECRETION AND CONTAMINATION OF MILK. 13 
22. Time of Secretion. 
Some authorities believe that milk is secreted to a large 
extent at the time of milking, since the udder has room for only 
Fig. 3.—A section through a quarter of a cow’s udder. From a photo- 
graph (Cornell Univ. Experiment Station). 
a portion of the milk yielded by the cow at a milking; when a 
cow is excited or disturbed at that time, she may fail to produce 
as much milk of the same quality as usual. 
