412 On some new Researches in Animal Chemistry. 



vestigations which it is impossible for me, consistently with 

 my other duties, to find time for carrying on, and I leave the 

 subject without reserve to those who have more leisure. 



I would remark, that the composition of lignia must be 

 that of lignin plus 2 atoms of oxygen given up by the nitric 

 acid in becoming hyponitrous acid ; and I would further 

 observe, that the latter acid and lignia forming an insoluble 

 compovmd, may probably be employed as mutual tests of each 

 other's presence in combinations. 



LXII. On some new Researches in Animal Chemistry. Ex- 

 tracted from a Letter from Professor* Liebig to Dr. A. 



W. HOFMANN*. 



I AM at present occupied with the investigation of the con- 

 stituents of the animal fluids which are found without the 

 blood and lymphatic vessels. The fluid from flesh, for ex- 

 ample, reacts strongly acid, and the question was, whence 

 arose this acidity ? After overcoming more difficulties than I 

 have ever experienced in any investigation, I have for the 

 first time indisputably proved that free lactic and phosphoric 

 acid exist in the whole organism wherever muscle is found. 

 How curious, that in the absence of all proofs on the part 

 of the opponents of lactic acid, I should now demonstrate 

 to them its existence in the flesh of oxen, fowls, calves, and 

 sheep, by preparing and analysing the most beautifully cry- 

 stallized zinc and Hme salts! How wonderful, that in the 

 animal organism acids and alkaUes are found separated by a 

 membi-ane, constituting myriads of little galvanic circles, 

 M'hich, as such, must produce chemical and electrical effects ! 

 To the latter class I refer all the observations of Matte ucci, 

 which can now be easily explained, 



I have further found that the flesh of the muscles of oxen, 

 fowls, sheep, calves, and the carnivorous pike contain crea- 

 tin, prepared by Chevreul eleven years ago, and which, from 

 Berzelius's not being able to reproduce it, has since then, in 

 a measure, disappeared from the field of science. Creatin 

 is a beautiful substance, having the formula CgNgHjiO^-. 

 At the temperature of 100° C. it loses 2 equivs. of water, and 

 becomes C8N3H9 04= glycocoll + ammonia or caffein + 

 amidogen and water. Heated in a stream of hydrochloric 

 acid, creatin loses 4 equivs. of water and takes up 1 of hy- 

 drochloric acid. By this treatment, however, its nature is 

 entirely altered, being now converted into a beautiful organic 

 base, the properties of which are totally different from those 



* Communicated by the Chemical Society ; having been read Dec. 21, 

 1846. 



