On Milk and its Adulterations. 135 



hemp seed in lieu of almonds, because of its greater cheapness. 

 They thus dilute the milk of cows to almost any extent they 

 j)lease, without altering its colour or opacity, and correct its taste 

 bv a little coarse sugar. 



This fictitious railk may be detected, however, by the oUy 

 nature of its curd. When the latter is pressed between the 

 fingers, or on paper, the oil exudes from it, which is not the 

 case with the curd of pure milk. 



That portion or part of the milk which is least influenced by 

 variation of food, &c. in the cow, is the caseous portion, or curd. 



Four specimens of milk were obtained by the author from 

 dairies on different sides of Paris, and one other was taken from a 

 cow, and immediately brought to him. Three hundred grammes 

 of each of these were warmed, and treated with equal quan- 

 tities of vinegar. The curd of each being drained, and equally 

 pressed between folds of soft paper, afforded, those from the 

 dairies, each twenty-nine grammes of cheese, and that from the 

 cow, thirty grammes. 



A second experiment, gave within a small fraction, the same 

 result. Taking the quantity of this caseous matter as a type of 

 the purity of milk, other equal proportions of milk were mixed, 

 «ach with an equal weight of water, and treated in the same 

 manner, when it was found that the quantity of cheese was ex- 

 actly one-half. 



In a third experiment, the milk was diluted with twice its 

 weight of water, and the cheese was precisely one-third. 



The last experiment was repeated, with the addition of sugar 

 to the milk and water. When the cheese was extracted, the whey 

 cautiously evaporated to the consistency of extract, treated with 

 boiling alcohol, filtered and evaporated, the sugar which had been 

 added was recovered. 



To distinguish the milk which is adulterated with emulsion 

 of almonds or of hemp-seed, 150 grammes of pure milk were 

 united with 150 grammes of emulsion of sweet almonds, and the 

 curd was separated by vinegar, with the aid of heat. Being well 

 pressed, it weighed 16 grammes /j. Then another mixture was 

 made, in the proportion of 100 grains of milk to 200 of emul- 

 sion, and this furnished 10 grammes and 18 decigrammes of 

 curd, which, it will be observed, is proportionate to the prior 



