1813.] Chemical Properties of Animal Funds. 425 



alkali left undissolved by the alcohol, neutralized by the sulphuric 

 acid, produced only sulphate of potash. I know not how far this 

 observation is applicable to other kinds of milk, or to milk taken 

 from other individuals. 



Cheese, which is destined to be part of the nourishment of the 

 young animal, has very peculiar characters, which, as it would 

 seem, fit it for tliis office. It admits easily of incineration, 

 affording a white ash which contains no alkali, and which forms 

 as much as (>'b percent, of the weight of the cheese. This ash 

 contains principally earthy phosphates with a little pure lime : 

 but it contains neither alkali nor oxide of iron. Cheese digested 

 with concentrated muriatic acid yields the greater part of its 

 phosphates to the acid, and it afterwards burns without leaving 

 any ash. But the cheese may be precipitated from the milk by 

 an acid without losing its phosphates. It appears, then, that the 

 latter are not yet formed, but that a slight affinity only is requisite 

 to their production. We may conclude that Nature has thus 

 sought to assist the digestive powers of the young during a period 

 of their lives in which there exists in the economy the greatest 

 demand for earthy phosphates for the purposes of ossification, 

 which is at that time advancing so rapidly. 



Cheese is generally considered as a substance insoluble in 

 water, and yet a great part of it is in actual solution in milk. A 

 solution of it in water may be obtained, if cheese precipitated by 

 an acid and well expressed, be digested with carbonate of barytcs 

 or carbonate of lime. The carbonate is decomposed with effer- 

 vescence, and the cheese quitting the acid is dissolved. The 

 solution is yellowish, and resembles a solution of gum. Evapo- 

 rated to dryness it leaves a yellow mass, which easily redi6sol\ es 

 in water. The solution boiled in an open vessel becomes covered 

 with a white pellicle, precisely as milk does, and acquires the 

 smell of boiled milk. The membrane is almost insoluble in 

 water, and appears to be a product by the action of air on the 

 dissolved cheese. 



With the mineral acids cheese produces the same combinations 

 as albumen and fibrin, although the neutral combinations are less 

 soluble than those of fibrin. A great excess of acetic acid is 

 required in order to dissolve the cheese, and the neutral combi- 

 nation with this acid appears to be insoluble. Cheese is easily 

 dissolved in alkalies. Its solution in acetic acid, as well as in 

 ammonia, becomes covered with a small quantity of cream every 

 time that the cheese has not been well separated from the butter. 

 Alcohol converts cheese into an adipocirous and fcetid substance. 



Butter and sugar of milk are so well known, that no additional 

 information can result from my experiments on them. 



