yS ON THE ACID OF MILK. 



tcrs contained hoi, are five; namely, acetous acid, benzoic acid, muriate 

 of ammonia, muriate of soda in part, and uree. These that 

 are insoluble in it are more numerous, as at least eight may 

 be reckoned ; namely, four phosphates, two sulphates, mu- 

 riate of soda, and uric acid. On treating with water these 

 eight substances insoluble in alcohol, we dissolve the phos- 

 phates of soda and ammonia, a very little phosphate of 

 magnesia, the muriate of soda, the sulphates of potash and 

 soda, which are known by their crystallization, and which 

 may be separated from one another in a certain degree by 

 solutions of platina. We may judge that phosphate of mag- 

 nesia is present by means of potash, which will precipitate a 

 small quantity of this earth. 



The substances insoluble in water then are the phosphate 

 of lime, some phosphate of magnesia combined with phos- 

 phate of ammonia, and uric acid, which may be separated 

 in the usual way. This method however differs very little 

 from those that have been given by other chemists ; and I 

 describe it here in a concise manner, because it is intimately 

 connected with my subject. 



Part III. Of the acid of milk. 



Milk quite Milk as soon as it comes from the mammary glands red- 



fresh contains dens litmus paper: it contains therefore a free acid. AVhen 

 I discovered this fact near eighteen months ago, I endea- 

 voured in vain to obtain it pure* in order to examine its pro- 

 perties I and all my endeavours since that time, to attain the 

 same object, have been equally fruitless. 

 Probably the Though every thing leads us to believe, that it is the ace- 

 acetous. tous aci,^ y e t it is the same with respect to it, as with re- 

 spect to the acids of sweat and urine: to pronounce decidedly 

 on its nature, it was necessary to separate it, and combine 

 it afterward with salifiable bases. This at length I effected, 

 by pursuing a method analogous to that, which enabled me 

 to obtain the acid of urine. 1st, I evaporated the milk to 

 dryness: 2dly, T treated the residuum with barytes water, 

 to saturate the acid: 3dly, I evaporated to dryness again: 

 4thly, I treated it with alcohol, to dissolve in part the ex- 

 tractive matter, and particularly to collect the caseous sub- 

 stance, so that none should remain suspended in the water: 



5thlv, 



This j roved. 



