Contamination of Milk. 31 



the milk-secreting cells. The other alternative is the 

 possible direct contamination from the outside by or- 

 ganisms passing up through the milk duct, and so 

 spreading through the open channels in the udder. 



FIG. 7. SECTIONAL VIEW OF UDDER. 



Teat with milk duct connecting the exterior with the milk cis- 

 tern. Milk sinuses which conduct the milk from the secret- 

 ing tissue to the milk cistern. (After Moore & Ward.) 



Number of bacteria in fore-milk. If a bacteriological 

 examination is made of the milk drawn from each teat 

 at different periods during the milking process, it will 

 be found that the fore-milk, i. e., the first few streams, 



