I 297 3 



• From the publication before remarked, it appears 

 that there is in milk an acid volatile alkaline, and 

 an un(^uous particle, befidcs other chemical proper- 

 tics; among the reft, a fixed alkali j a muriatic or 

 briny acid; it is alfo remarked, that the volatile 

 fubftance which flies off, and occafions the particular 

 odour, is peculiar to animal bodies -, and although 

 from its volatility it eludes every enquiry into its 

 fpecifick nature, yet there is reafon to imagine that 

 it is a confiilcnt part of the milk, and confequcntly 

 not deftitute of utility. 



This is the firft time I ever met with any account 

 of the volatile part of milk; but from which I ex- 

 pedl many ufeful obfervations may be made. It is 

 fuppofed that churning effeftuates a chemical 

 change in the cream; and that the particles of 

 butter cannot be produced by any other method;— 

 that heating cream when on the milk, caufes the 

 volatile particles to fly off, and fets the cheefy 

 particles more at liberty ; they are apt to rife with 

 the cream and incorporate with it, which caufes the 

 butter in a very little time to become foul and 

 rancid, as I fuppofe the cheefy particles foon fcpa- 

 rate from the butter ; which in a fhort time makes 

 it foul, as it acquires more of the nature of butter- 

 milk; that the cream that rifes without the aid of 



warmth^ 



