10 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



of the alveoli and ducts, as has been suggested, because 

 when milk is drawn from the udder at the end of the 

 first phase with a milk tube or catheter the composition 

 of the first and last milk is about the same; but as soon 

 as the teats are manipulated, thus beginning the second 

 phase, the per cent, of fat is increased. The milk se- 

 creted during the first phase contains a lower per cent, 

 of fat than that formed in the second phase. The per 

 cent, of other solids is nearly the same in the milk of 

 both phases. The original ferments or enzymes, except 

 oxydase, are present in greater quantity in milk of the 

 second phase than in that of the first. The first milk 

 drawn from the udder contains more oxydase than the 

 end milk. 



