MILK. 



193 



as a scientific fact, it is well worthy of remark here. 

 To prove the truth of the well-founded popular impres- 

 sion that the first drawn milk is poorer in fat than the 

 last drawn, or ^'the strippings," Dr. Sharpless tested 

 another pure Ayrshire cow with the following result : 



Specific gi-avity 



Cream 



Sugar 



Caseine 



Ash 



Fat 



Water 



First third. 



1.029 



6 per cent. 

 4.49 

 3.06 

 .54 

 1.78 

 190.13 



Second third. 



1.032 



9 per cent. 

 4.80 

 4.25 

 .58 

 3.03 

 87.34 



Last third. 



1.027 

 11 per cent. 



4.50 



3.90 

 .54 



4.03 

 87.03 



Dr. Sharpless' conclusion, after making a large number 

 of tests, was that no one cow's milk is as uniform in com- 

 position as the whole milk of a herd, for as the cows will 

 vary either way a general average of remarkable consist- 

 ency is procured. This will no doubt accord with the 

 general experience of dairymen. But then there are 

 some cows, especially among the Jerseys — as was the case 

 with the selected test cow Nellie, referred to in Chapter 

 XII., and which was chosen for her uniformity in pro- 

 duct — which vary little in the quality of the milk under 

 the same feeding and other conditions. 



Milk is the final result of gestation and is coincident 

 with parturition. For some days previous to calving, 

 preparations are being made in the mammary glands, 

 which is commonly called the udder, for the secretion of 

 the milk, which Nature intends as a provision for the 

 support of the calf. This preparation of the glands 

 consists in an gedematous tumefaction, or a soft pulpy 

 swelling by which the udder is largely increased in size. 

 A thin serum can often be expressed from the teats during 

 this preparatory period, which begins from a month to two 

 months before the calf is born. This preparatory period 

 is much longer with a heifer with its first calf, and 

 usually begins a short time after the beginning of gesta- 



