1813.] Chemical Properties of Animal Fluids. 201 



2. I digested 10 grammes of the dried powder in cold water. 

 The albuminous portion softened, and became gelatinous. I 

 separated by the filter the liquid from the insoluble part, and 

 washed the latter repeatedly with boiling water. The undissolved 

 albumen dried in the filter, weighed 6"47 grammes, and did not 

 give up its earthy phosphate, by subsequent digestion in muriatic 

 acid, as this acid remained clear on saturation with an alkali. 



3. The solution which had passed the filter was evaporated to 

 dryness, during which thick membranes formed at the surface, 

 and the solution gelatinized before it was perfectly dry. I 

 digested this residue in alcohol, whilst it was still gelatinous; 

 the spirit assumed a yellow colour, and on evaporation left an 

 alkaline yellowish deliquescent mass, weighing 0*92 grammes. 

 This consisted of soda, holding albumen in solution, of muriate 

 of soda, and muriate of potash, of lactate of soda,* and of an 

 animal matter which always accompanies the lactate. 



* Tn mentioning the lactate of soda in this place, I wish to make some obser- 

 vations on the lactic acid, as one of the constituent parts of all animal iluids. 

 Ii i- well known that tlii* acid was discovered bj my illustrious countryman, 

 Scheele. Latterly, the French chemist's have examined this acid ; and Four- 

 rroy, Vauquelin, Thenard, and Bouillon La Grange, have sought to prove that 

 •elc was mistaken in the supposed peculiar nature of this acid, and that it is 

 only a combination of acetous acid with some animal matter. 



files ■ chemists, however, have made no attempts to obtain this animal matter 

 M parate from the acid, and have never succeeded in producing the lactic acid 

 by means of the acetic ; but this is the proof which they give of Scheele being 

 in an error. Lactic acid is combined with an alkali, the resulting lactate is 

 distilled, with concentrated sulphuric acid, and in the receiver is obtained a 

 mixture of sulphurous, muriatic, and empy rcutnatic acetic acid, the latler of 

 srbich is purified; and hence it is, that we are informed that the pretended 

 tic arid i> only the acetous united yiith some animal matter. But it appears 

 me, that the French chemists have only cut the Gordian knot; for one of 

 properties of the lactic acid is to be incapable of volatilization, and it is 

 a property of the sulphuric acid to change many organic substances with 

 which it is distilled, into the empvreumatic acetous and sulphurous acids. 

 By a parity of reasoning, almost every one of the vegetable acids might be 

 red to be only arctic acid, combined with some matter which deprives it 

 ' ' K- volatility, without destroying its other acid properties; and in fact it is 

 i.i'i , that Bouillon La Grange has inferred that the malic and gallic ucids are 

 only varieties of the acetic. In an analysis of muscular tie?!), which I made 

 in the year 1806, I found that the humours of the muscles contained a free 

 I, which, b) many experiments, I discovered to have all the properties 

 3i hide attributes to the lactic acid. I collected a quantity large enough 

 rar examination, and I succeeded by different methods, in obtaining it in 

 iter purity than Scheele hod procured his, I examined a great number of 

 ■ta saline combinations, with alkalies, earths, and metallic oxides, the parti- 

 cular! ul which are given al length in the second volume of roj Treatise on 

 Animal Chemutrg, Stockholm, 1808, p. 430, <v seq. Ef, thi . fore, it i> allowed, 

 two acids thai prodnce aline compounds different from each oilier cannot 

 be identical in their nature, the distinction between the lactic ami the acetic 

 cannot in- coutrot rred', It Is since that time that Ihavediscovered'Hie 

 id, in .• or combined, in ail animal fluids. 



I have observed, in their analysi I fluids, that the 



'oiic solution, when, evaporated, leaves a yelli it extractive 



. ot late, more attention has been paid to this extract, and if l mistake 



