202 Prof. Latham, Further observations on the [March 6, 



The theory which I have here advanced depends entirely on 

 the possibility of the amido-acids being converted in the living 

 body into urethanes or alcoholic carbamates. Is there then any 

 proof of such a change being effected, any proof in fact of the 

 existence in the body of carbamic acid ? 



Assuming the existence of these urethanes, let us introduce 

 into the alimentary canal some substance with which they may 

 form compounds similar to urea. If sarcosine or methyl gly- 

 cocine be such a substance we should have as the result of the 

 combination — 



co {nh 2 + ch 4cooh = oh • r + C0 1nh 2 



alcoholic car- sarcosine alcohol methyl hydantoic acid 



bamate or 

 urethane 



and methyl hydantoic acid being an unstable body would be trans- 

 formed into methyl hydantoin — 



C0(S„ CH .- 0H « - ° 00H ™ f ■ GH " " I H * + HO 



INH, * = 00 (NH 00 



methyl hydantoic acid methyl hydantoin 



If then after the administration of sarcosine to a living animal, 

 methyl hydantoin appears in the urine, this would furnish a strong 

 argument in favour of the formation and existence of the urethanes 

 in the system. I find that experiments have been made with 

 sarcosine by Schultzen, Bauman and Hoppe-Seyler, Salkowski and 

 von Mering*. Most recently by Dr J. Schiffer, who gives an excel- 

 lent summary of the experiments and views of the others, together 

 with an account of his own observations and experiments. From 

 this paperf I take the following extracts : 



"Few investigations in the range of physiological chemistry 

 have in recent times excited so much attention as those of Schult- 

 zen on the transformation of sarcosine in the animal body. In 

 conjunction with Leon v. Nenki (Zeitsch.f. Biologie, Bd. VIII.) lie 

 had previously found on giving glycocine as food the amount of 

 urea excreted corresponded with the amount of N given....... He 



repeated his experiments with methyl glycocine or sarcosine. In- 

 creased secretion of urea did not take place ; on the contrary two 

 new bodies appeared in the urine, both having an analogous com- 

 position, the one compounded of sarcosine and carbamic acid, the 

 other of sarcosine and sulphamic acid. The first of these bodies 



* Berichte dcr deutsch. chem. Gesell. Bd. v.— vm. 

 + Zeitsehrift fiir physiol. Ghemie, Bd. v. s. 267. 



