250 LACTIC ACID; 



SECTION IV. 



On the Sugar of Milk. 



Whether acetic The formation of acetic acid does not arife merely from the 



acid in milk alteration of the fugar of milk ; and though the experiments 

 anfe f.om the , ■ ^ * ' . . J> Ti r . 



decompofttion of already deicnbed admit or certain conjectures, I have alcer- 



its fugar. tained whether a like quantity of fugar of milk could be ob- 



tained' from frefh ferum and a ferum expofed for twelve days 

 at a temperature from 14 to 20 degrees. 



A little fugar is I have found that (our milk affords a fomewhat lefs quantity 



decompofed by f f U g ar f milk, which proves, that a portion of the faccharine 

 fbnding. 6 . , . ' ' . 



matter was employed in tormmg a quantity or acetic acid. 



We may therefore obtain carbonic acid, alcohol, and acetic 



acid, either by confining whey in clofe veffels, or by leaving 



it expofed to the air. 



Other experiments made on pare fugar of milk indicated 



nothing remarkable. 



Habitudes of It does not redden tincture of turnfole. When diffolved 



fugar of milk. j n wa t er anc j expofed for a long time to the air, it does not 

 become acid. By diftillation it affords acetic acid along with 

 the known products. 



It is foluble in weak acetic acid. If a fmall quantity of 

 freth gafeous matter be added, it is foon found that the liquor 

 holds it in folution. By pouring in a few drops of alkali to 

 faturate the excefs of acid, it lofes its trarifparency, becomes 

 turbid and milky, with a mild tafte refembling that of milk, 

 anoV preferves its opacity for a considerable length of time. 



General refults The following refults are deducible from the preceding 



refpecYing milk. f a $ s .__ 



1. New milk reddens the tinfture of turnfole. 



2. The^pheefy matter may be feparated without contact of 

 the air. 



3. The ferum does not retain the acids made ufe of to coa- 

 gulate milk. 



4. Diffillation either of milk or of fugar of milk to drynefs, 

 affords the acetic acid. * 



5. The formation of carbonic acid and alcohol is owing to 

 muco-facchaiine matte$» 



6. A quantity of acetic acid is formed by the fermentation 

 of thcfe fubftances, 



7. The 



