MIL

M. I L

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whey Contained phofphat of lime and of mag-jiefia along with fome iron.

The whey, after the precipitate with lime-water had been removed, was then treated withoxalic acid and evaporated in a retort to a fmallbulk in the manner deferibed by Scheele . I hefluid expelled by evaporation was collefted andfound to be {lightly four and fomewhat empy-reumatic, but the liquor which remained in theretort was reddifh-brown, and very four, andcontained by far the greater part of the laddieacid. To this liquor which was as thick asfyrup, a large quantity of ftrong alcohol wasadded, which eaufed the-reparation of a brownthick vifeous matter, not the leaft acid, foluble inwater, giving a precipitate with galls, and afford-ing carbonat of ammonia by diftillation. By Hand-ing it depofited' fome fugar of milk. It there-fore confided of fugar of milk apparently un-altered by the fouring of the milk, and of apeculiar animal matter. The alcoholic folutionwas highly acid and of a dark red, and by thefrequent boiling it had acquired a dark colourand empyreumatic frnell. The alcohol beingdiftilled off and water added, the liquor wasrepeatedly treated with fulphuric acid ar.d dif-tilled, whereby, on the one hand, there was aconftant feparation of a bituminous matter, andon the other a portion of perfect acetous acidwas conftantly obtained by diftillation. By thisingenious method the whole was refolved intoacetous acid and into a peculiar bituminousmatter diffolved therein, and to which the acidowes thofe properties by which it differs fromcommon acetous acid.

From thefe and other refearches by the famechemifts, it appears therefore that there is nofuch diftinfft acid as the laElic of Scheele , butthat it is acetous acid holding in folution aquantity of animal matter, to which it owes theproperty of giving a brown precipitate withgalls, a yellowifh-grey with nitrat of mercury,and a brown with acetite of lead ; and from thefame caufe alfo it gradually darkens in colourand depofits a brown matter by evaporation.'Ihe above chemifts alfo obferve that an acidprecifely fimiJar to the latlic is produced bydiffolving gluten in vinegar, by fermenting to-gether a mixture of fugar, water and gluten,and it alfo is die fame as the fours procured inftarch-making by die fermentation of wheat flourand water.

The la£lic acid diluted with water, and longkept m a warm place, gradually lofes the wholeat its acidity, depofits a brown matter, acquires

f . Memoirs R. Soc. of

a fetid imell, and on adding lime givesmoniacal vapours. The fame effects are alioproduced by a folution of gluten in vinegar.

The nature of this animal matter which byuniting with acetous acid forms the lactic acidof Scheele , is not precifely afeertained. It isprobably the chief caufe of that fpontaneouschange by which milk turns four, and largelycontributes to form the acetous acid which isthen generated, but it is not totally decompofedby the acid fermentation, fince the acetous acidwhen formed diflolves a portion of it for atime, and thus protects it from further change.This matter appears alfo to differ from the curd,fince on the one hand, when depofited from thelactic acid by evaporation, it fhews no refem-blance to curd; and on the other hand a folu-tion of curd in vinegar will not be difcolouredby evaporation, nor can it be brought to depofitany fubftance fimilar to the other. It is moltprobable therefore that gluten muft. be added tothe conftituent parts of milk.

Milk is fufceptible of the vinous fermentationfo as to be made to yield an ardent fpirit byfubfequent diftillation, but it is not very eafy toferment milk, and it always turns four at thefame time. The Tartars and other Afiatic na-tions have been from time immemorial in thehabit of preparing an- intoxicating liquor frommare’s milk. This is called koumifs, and thepropefs is thus given by Dr. Grieve. e Takeany quantity of mare’s milk, dilute it with a ■*fixth of water, pour it into a wooden vefTaJ, andadd as a ferment about one-eighth of very fourmilk, or better, of old koumifs, cover the veflel.with a thick cloth and keep it in a moderatetemperature. After Handing twenty-four hours,a thick coagulum rifes to the top, which muftbe well mixed by beating. After repofing foranother day, it is again ftirred till it becomesquite homogeneous, and in this ftate it formsthe koumifs, which has an agreeable fweetifh ,acefcent tafte.

Milk-, in the ftate of koufttifs does not eafilychange by keeping. By diftillation it yields aconfiderablc quantity of alcohol, as much (ac-cording to Pallas) as- one-third of its bulk. Theentire milk appears effential to the produdfionof ardent fpirit, as well as frequent agitation tomix- the. conftituent parts which the acid haseaufed to feparate.

The fugar of milk (which is never abfent) willnaturally be looked to as the fource of the alco-hol and the caufe of the vinous fermentation.But Meffrs. Fourcroy and Vauquclin deny this:.

hdinb. for 1788