INFLUENCE OF THE STATE OF PREGNANCY. 539 



of this or that food, except by a much more prolonged series of careful 

 observations. 



If we compare the quantity of albumen and casein contained in the 

 food, with that yielded in the milk during the four days' experiments of 

 Dr. Playfair, we shall find no perceptible relation between the two quan- 

 tities. Thus, the cow on the — 



Of Casein 



and yielded 0-93 lbs. 



1-0 " 

 0-75 " 

 «; 0-94 " 



So that, whether, as on the third day double the quantity was eaten, or, 

 as on the fifth, little more than half as much as was consumed on the 

 second day, the produce of cheesy matter in the milk was sensibly the 

 same, on each of the three days. 



We must not, however, from these experiments, infer that the kind of 

 food really has no influence upon the quality of the milk — for this con- 

 clusion is contradicted by general experience. We must wait rather for 

 renewed and more extended practical researches, by which both our 

 theory and practice may probably be amended, and by which the con- 

 clusions may be reconciled to which they respectively lead us. [See the 

 following Lecture " On the feeding of stock.*^] 



10°. State of pregnancy. — I have already stated (p. 535), that the 

 richness in cream diminishes as soon as the cow becomes pregnant. The 

 same is no doubt true also of the amount of cheese which the same 

 volume of milk will be capable of yielding. It must become poorer in 

 every respect, or else considerably less in quantity (p. 541), as soon as the 

 cow is with calf, since a portion of the food which might otherwise have 

 been employed in the production of milk, must now be directed to the 

 nourishment of the young animal in the womb of the mother. In the 

 experiments to which I have just directed your attention in regard to the 

 effect of the kind of food upon the quaUty of the milk, the state of preg- 

 nancy of the animal was not taken into consideration, though, as I have 

 already said, this must necessarily exercise an important influence upon 

 the quality of the milk, whatever be the kind of food upon which the 

 animal may have been fed.* To this the want of accordance between 

 theory and experiment is probably in part to be ascribed. 



11°. Individual fonn and constitution of the animal. — But it is well 

 known that animals of the same breed, fed on the same food, will yield 

 milk not only in different quantities, but also of very different quality. 

 In regard to the form, Mr. Youatt states that the " Milch cow should 

 have a long thin head, with a brisk but placid eye, — should be thin and 

 hollow in the neck, narrow in the breast and point of the shoulder, and 

 altogether light in the forequarter — but wide in the loins, with little dew- 

 lap, and neither too full fleshed along the chine, nor shewing in any part 

 an inclination to put on much fat. The udder should especially be 

 large, round, and full, with the milk veins protruding, yet thin skinned, 

 but not hanging loose or tending far behind. The teats should also stand 

 square, all pointing out at equal distances and of the same size, and al- 



' Both of the cows experimented upon by Boussingault were with calf, Dr Piayfoir doe» 

 not mention whether his was w or not. 



