M I L

M 11.

C 104 )

to be the cafe, firft, becaufe pure fugar of milkmixed with water and leaven, and expofed tomoderate heat will not ferment as commonfugar does, nor yield any alcohol: and fecondly,becaufe nearly as much fugar of milk is foundin whey thoroughly foured by keeping, as infrelh milk. But as the above chemifis werenot able to procure any alcohol from milk four-ed in the common way, it is obvious that itcannot be at all inferred from thence that thefugar of milk is not decompofed in the procefsthat does form alcohol; but only that this fub-ftance does not appear adlive in the formationof the ladlic (that is, the acetous) acid. Neitherdoes it at all follow that fugar of milk is notdecompofed in entire milk, becaufe when pre-vioufiy feparated from milk it cannot then bemade readily to ferment. It is probable on theother hand that both the acetous and the vinousfermentations are going on at the fame time inmilk whillt converting into koumifs, and thatthe materials for thefe two precedes are not thefame as in common vinous fermentation (theacetous being there chiefly a continuation ofthe vinous procefs), but are, partly at leafl,diflindl, the gluten contributing chiefly to theacetous, and the fugar of milk to the vinous.

Though the milk of different animals is foundto be effentially the fame in the number andchemical nature of the feveral ingredients (asfar as has been examined), yet a very confider-ahle difference is found in the proportion ofthefe fubftances and in fome of their fenfibleproperties. The experiments of Parmentier are.particularly curious on this fubjedl. The kindsof milk that he examined were, firft, cow’smilk as a ftandard, to which were comparedthe following, viz. woman’s, afles’, goat’s, ewe’ssnd mare’s milk.

Woman’s milk is fweeter than cow’s, andthinner, but it is of all others, that which variesrnoft according to the flate of body, conflitu-tion, age, &c. of the perfon whence it is drawn.The cream is on the whole more copious thanof common cow’s milk, but it differs peculiarlyin this, that neither agitation nor any otherknown means will entirely feparate the butter ;the utmoft effedl of thefe means being only togive the whole cream fomewhat of an undluousconfidence, without effecting any feparationinto butter, curd, and whey.

Human milk alfo depofits part of its curd bymere reft, which is found flicking to the fidesof the veffel which holds it. Though fweeterto the tafte than cow’s milk it does not con-tain fenfibly more fugar.

Affes’ milk more refembles the human thanany other. The cream is in fmall quantity, byagitation it gives a butter which is foft, white,and nearly taflefefs. It foon becomes veryrancid owing probably to its retaining a portionof the acid. By Handing, it depofits much ofthe curd even before it becomes four.

Goat’s milk is very thick, yellowifh, andpleafantly flavoured. It is fomewhat denferthan cow’s milk. The cream is remarkablythick and un&uous, and will keep a long timewithout growing four or fenfibly changing. Byagitation it gives a very firm, folid, and whitebutter, to appearance very free from all admix-ture. This milk alfo abounds in curd, fo thatwhen heated, a much thicker pellicle rifes, andwhen coagulated by any of the ufual methodsthe curd is fo abundant that the whey is withdifficulty feparable. It is alfo of a very gelati-nous denfe confiflence. The fugar of milk isfmall in quantity, but feparates with eafe.

Sheep’s milk refembles cow’s very clofely intafte and appearance. It yields abundance ofcream, which by churning affords much butter,but which always remains very foft. The quan-tity of curd is remarkably large, and it has avery fat and undtuous appearance, and a taftewhich is peculiar to it, and is always very dif-tinguifhable in ewe-milk cheefe.

Mare’s milk is thin and infipid, and does notcoagulate with vinegar. It is remarkable for thefmall quantity of cream which it gives and theextreme difficulty of feparating the butter from itby agitation. The whey contains fulphat of lime,which has not been found in any other milk.

The above-mentioned fpecies of milk all re-refemble each other effentially in the numberand general chemical nature of the ingredients,but great diverfity appears in their refpedliveproportion, and apparently in the mode of mix-ture. Thus with regard to the cream, cow’sand flteep’s milk yield it eafily by repofe, itsconfiflence is greater than in the others, andthe butter feparates more perfedtly. There isan equal difference in the confiflence of thecurd, that from cow’s and fheep’s milk beingdenfe, and readily feparating by the ufual coa-gulating fubftances, but the cuid fiom afs s andmare’s milk always remains thin, and almofl ofa creamy confiflence. I he only general agree-ment which the authors of thefe experimentshave been able to make on this fubjedl, is thatwhere the curd is tough and gelatinous, thebutter is readily feparable from the cream, andall the conflituent parts of the milk are moreeafily obtained by chemical means.