of lactate of zinc.

1 eq. anhydrous Lactate of lime 109 100.00 100.00 100.00

The lactate of zinc, prepared from flesh, was also analysed.

Gm.

Gm.

p.c.

0.499 of lactate of zinc, when heated to 212°, lost 0.068 of water = 13.6 1.3295

0.1775

Mean loss

13.3

13.45

Its formula

0.564 gm. of crystallised lactate of zinc left, when ignited, 0.1645 gm. of oxide of zinc = 29.16 per

cent.

0.3153 gm. of anhydrous lactate of zinc left, when ignited, 0-1052 gm. of oxide of zinc = 33.31 per

cent.

0.5690 gm. of the anhydrous lactate yielded, by combustion, 0.6125 gm. of carbonic acid, and 0.213 gm. of water.

0.2260 gm. of the anhydrous lactate yielded, by combustion, 0.244 gm. of carbonic acid, and 0·0838 gm. of water.

Hence, the crystallised lactate of zinc contains*____

* According to the investigations of Engelhard and Maddrell, lactate of lime, prepared by Frémy's process, contains 5 eqs. (= 29 p. c.) and the lactate of zinc 3 eqs. (= 18 p. c.) of water of crystallisation. It is possible, that this variation in the

The ultimate analysis of the anhydrous lactate of in the an

hydrous state.

1 eq. anhydrous Lactate of zinc 121.5 100.00 100.00 100.00

azotised

is lactic

From the preceding analysis it evidently appears The nonthat the non-nitrogenised acid occurring in the acid of flesh animal organism is identical with the acid formed acid. in milk when it becomes sour, and into which sugar of milk, starch, grape sugar, and cane sugar are converted by contact with animal substances in a state of decomposition.*

The inorganic Constituents of the Juices of Flesh.

consti

Chevreul has already directed attention to the Inorganic very large quantity of inorganic substances contained tuents of in the juice of beef. In his experiments they flesh.

amount of water in these two salts depends on this, that the lactates from flesh were crystallised by slow evaporation, and not by cooling.

* From the most recent researches of Engelhard and Maddrell, lactic acid appears to be a bibasic acid. It forms an acid salt with baryta, and its formula must consequently be doubled.

the juice of

Alkaline salts pre

in it.

amounted to rather more than a fourth part of the weight of the matters dissolved in the soup when the flesh is boiled with water. Of the saline mass which he obtained by drying up and incinerating the solution, 81 per cent. were found soluble in water, and the insoluble residue of 19 per cent. consisted of 5.77 of phosphate of lime and 13.23 of magnesia.

It is evident that alkaline salts are the prepondeponderate rating inorganic constituents of the juice of flesh, and that phosphate of lime is in the smallest proportion compared to those salts and to the mag nesia.

Importance of the inorganic constituents.

Now, since we may assume with a degree of probability almost amounting to certainty, that, in so perfect a machine as the animal organism, every part has its significance, I have thought it of importance to make some experiments on the nature of the mineral acids and alkaline bases occurring in the juice of flesh, and their mutual relations, experiments which, however imperfect, may still serve as points of departure for future researches.

The organised constituents of the body have been derived from unorganised matters, and return to the unorganised state; and it is especially with the unorganised substances that our researches must begin. If now it can be demonstrated by investigation that certain inorganic constituents occur in the flesh of all animals, and are never absent therefrom, it will follow that they are essential to the function of the muscles, those most complex parts of the organism;

while, on the other hand, a variation in their relative proportions enables us to infer a corresponding variation in some vital action.

When the juice of flesh (extracted as formerly described, and therefore diluted with water) is evaporated, even without the addition of baryta, it acquires at last, even when the temperature never exceeds 112°, a brown colour, and a taste of roast meat, and leaves when ignited an ash, which may be burned white, although with some difficulty. This ash dissolves almost entirely in water, and in this solution acids occasion no effervescence; the ash, therefore, contains no alkaline carbonates. A more minute examination shows that it consists only of alkaline phosphates and chlorides.

The ash of meat conalkaline phosphates and chlo

the juice of

tains only

rides.

phates are

The precipitate formed by baryta in the juice of No sulflesh in many cases dissolves entirely in diluted present. nitric acid; and in those cases in which a residue of sulphate of baryta is left, its quantity is so trifling that, for example, in the entire flesh of a fowl or of a fox its weight cannot be ascertained. Sulphates or sulphuric acid are therefore not present in the juice of flesh, a fact already ascertained by Berzelius.

The soluble salts obtained from the ash of the juice of flesh contain the different modifications of phosphoric acid, which are easily distinguished by their action on nitrate of silver.

It is well known that common or tribasic phosphoric acid forms three different salts with the

The differ

ent forms

of phos

phoric acid.

Characters

ferent

forms of tribasic phosphates.

alkalies; two of these, in their aqueous solution, have an alkaline, the third has an acid, reaction.

When a salt of phosphoric acid with 3 atoms of of the dif- fixed base, which is strongly alkaline, is mixed with neutral nitrate of silver, a yellow precipitate is formed, the alkaline reaction disappears, and the mixture, after precipitation, if a slight excess of the nitrate of silver be present, is perfectly neutral to test-paper.

The salts of tribasic phosphoric acid with 2 atoms of fixed base have also an alkaline reaction. They give with neutral nitrate of silver the same yellow precipitate, and the mixture, after precipitation, is neither alkaline nor neutral, but acid.

When these latter salts are ignited, they are converted into pyrophosphates (bibasic phosphates), which, when dissolved in water, exhibit an alkaline reaction, and give with neutral nitrate of silver a white precipitate. After precipitation, the mixture is neutral.

The salts of tribasic phosphoric acid with 1 atom of fixed base have a strong acid reaction. With neutral nitrate of silver they give the yellow precipitate formerly mentioned, while the mixture retains its acid reaction.

When ignited, these latter salts pass into metaphosphates (monobasic phosphates), of which the metaphosphate of potash is not soluble in water. Metaphosphate of soda dissolves readily in water, and gives with nitrate of silver a white precipitate,