T’. S. Hunt on the Constitution of Leucine. 63 
Art. XIl—Remarks on the Constitution of Leucine, with criti- 
cal observations upon the late Researches of M. Wutz; by 
S. Hun. . 
In the American Journal for January, 1848, p. 123, I made some 
suggestions as to the true composition of leucine and proposed a 
correction of the formula which had been deduced by M. Mulder 
from his analyses. After noticing the sulphuretted alkaloid thial- 
dine, lately discovered by Wohler and Liebig, I remarked that 
it corresponded to a normal species whose formula is C,, H, , NO,, 
which would be a homologue of glycocoll, “and very probably 
no other than leucine.” This correction I ventured upon with- 
out having before me the analytical results of M. Mulder, be- 
cause as I have stated, the formula deduced by that chemist, 
oe ,> Was irreconcilable with the law which MM. Ger- 
hardt and Laurent have announced as governing the composition 
of all azotized bodies. My proposed formula on the contrary, 
made this anomaly to disappear, and showing it a homologue of 
glycocoll, a substance formed at the same time with it, by the ac- 
tion of potash upon gelatine, at once explained the singular reac- 
tions of lencine with nitric acid, already described by M. Brac- 
connot. Not having it in my power to verify any farther my 
view, I left the matter to the consideration of chemists. 
In the Comptes Rendus de l’Acad. for Sept. 4th, 1848, there 
appears a communication from M. Cahours, who had submitted 
to analysis both leucine and aposepedine, (a product of the putre- 
action of caseine which Mulder had supposed to be identical 
With leucine,) and found the two substances to agree i compo- 
sition and to have precisely the formula which I had previously 
assigned. He has found that they form beautifully’crystalline 
Compounds with nitric and hydrochloric acids, and gives to the 
ormer the formula C,, H, , NO,, NO, M. Cahours has also 
Pomted out the relation between this body and thialdine and 
their homology with glycocoll. The sarcosine cbtaine : 
The Annales de Chimie et de Physique for Nov., 1848, contains 
amemoir on the same subject by MM. Laurent and Gerhardt, 
Conclusions as to its composition ard homologous relations. None 
of these gentlemen however have alluded to my observations 
published ten months previous, which appear to have escaped 
their notice, 
My formula requires C 54-9, H 9°99, N107, 0245. The 
analyses of Mulder show on comparison with this, a little defi- 
