24 



Production of Butter. 



Haidler obtained from 100 parts of cow's milk 



Butter 3-0 



Sugar of milk, and soluble salts .... 4*6 

 Casein, and insoluble salts . . , . . 5'1 



12-7 



and from 100 parts of milk, the produce of two cows, he procured 

 the following- salts : — 



Phosphate of lime . . . 0'231 . . 0-344 



Phosphate of magnesia . . 0-042 . . 0*064 



Phosphate of iron . . . O'OOT . . 0-007 



Chloride of potassium . . 0-144 . . 0-183 



Chloride of sodium . . . 0-024 . . 0-034 



Soda 0-042 . . 0*045 



0-490 0-677 



As respects quantity and quality of milk, there exists a wide 

 range, not only with regard to the yield from cows of different 

 breeds, but also from cows of the same breed ; the subject is 

 still further complicated, owing to diversities either in the 

 quality or quantity, or in both, caused by feeding on different 

 varieties of food ; which are again liable to variation with respect 

 to the period of gestation at which the milk has been collected. 

 Rapid changes in its character occur preceding and immediately 

 after parturition. 



Lessaign examined milk at ten different periods, four before 

 and six after parturition. The milk examined during the first 

 three of the former periods, namely, 42, 32, and 21 days before 

 parturition, contained no casein, but in place of it albumen ; no 

 sugar of milk and no lactic acid, but a sensible quantity of un- 

 combined soda. That examined eleven days before and just after 

 parturition, contained both albumen and casein; while milk, 

 eleven days before, and shortly after it, contained free lactic acid 

 and sugar of milk, but no free soda. The milks examined 4, 6, 

 20, 21, and 30 days after parturition, contained casein and no 

 albumen. 



A valuable series of experiments was instituted by Dr. Playfair, 

 for the purpose of ascertaining " the changes in composition of 

 the milk of a cow, according to its exercise and food ; " they are 

 published in the first volume of the ' Transactions of the Che- 

 mical Societ}^ of London,' in the course of which the author 

 expresses a regret, which all agriculturists must participate in, 

 *' that the value of the experiments is diminished by not being 

 extended over a series of days on each kind of food." " But in 

 England," the author adds, " where the price of ether is so ex- ^ 

 orbitantly high, the expense of such experiments is a serious 



