142 LACTIC ACID. 



not pointed out the aftion of fire upon this acid, nor its fpon« 

 taneous alteration in the air, the manner in which it comports 

 ilfelf with the nitric acid, &c. It is not known whether it 

 be totally decompofed by this laft, or converted into fome 

 other aciJ, particularly the oxalic acid. We are entirely un- 

 acquainted with the nature of its composition. Though it 

 prefents properties which refernble thofe of the acetous acid, 

 and lead to the probability that it nearly refembles it; we 

 cannot yet rank it with the vegetable acids. On the other 

 hand, nothing decifive can be ailerled with refpecl to its ani- 

 mal nature, becaufe no experiment has yet indicated the pre- 

 fence of azote, and it is yet unknown, whether it may afford 

 ammonia in its decompofition ; whether it be putrefcible, or 

 convertible into pruffic acid, &c. 



This general ftatement while it gives us a view of our 

 knowledge of the laclic acid traces, as it were, the fteps ne- 

 ceffary to be purfued in determining the place which this acid 

 ought to occupy, as to the number of well eftablifhed chemical 

 fe&s. 



SECTION II. 

 Concerning Milk and the cafeous Matter. 



On njilk, and its Before I proceed to defcribe the experiments I have made 

 constituent on t hj s ar tj c ] ej \i w \[[ be ufeful to prefent fome reflections 



parts. 



on milk, and its conftituent parts. 



Guiton, in the Encyclopedic Methodique, offers two quef- 



tions refpetting the existence of an acid in milk. He ex- 



preffes himfelf thus : 



Whether whey Does the whey exift in milk fuch as it is found after the fe- 



cxifts ready paration of the other conftituent parts ? Does it manifeft acid 



' properties on any other account, than becaufe it holds falts in 



folution, as all the analyfes fuppofe ? 



Milk cannot be If whey, adds the fame chemifr, exifted in milk, in the fiate 



reproduced by j t exhibits after the feparation of the butter and eheefe, we 

 the mixture of „ , , , . , , .... . . ,. - . 



its parts. fhould be able to reproduce milk by mixing thele three prin- 



ciples again in the fame proportions. But as this is not the 

 cafe, he concludes, that whey is the product of a true fermen- 

 tation. 



The examination of this firfl; queftion founded on experi- 

 ment, ought, I think, to prove that it will not be fufficient 

 to (hew whether whey exifts in milk, that we fhould mix the 

 three principles in the fame proportions, and re-produce that 

 fluid ; firfr, becaufe thefe principles are no longer the fame; 



and 



