1905-6.] Excretion of Allantoin in Thymus Feeding. 
95 
A Contribution to the Study of the Excretion of 
Allan toin in Thymus Feeding. By W. M ‘Lachlan, 
M.D. ( From the Research Laboratory of the Royal College 
of Physicians , Edinburgh.) Communicated by Dr D. Noel 
Paton. 
(Read January 8, 1906. MS. received January 12, 1906.) 
The establishment of the nature of the chemical relationship of 
the purin bodies, the diureides which form the chief end-product 
of proteid metabolism in birds and reptiles, with urea, the end- 
product in mammals, is not the least important of the valuable 
contribution of E. Eischer to physiological chemistry. The 
constant presence of diureides in the mammalian urine, and of 
urea in the urine of birds, shows that no hard-and-fast line exists 
between the metabolic processes in the two groups, and the fact 
that in the mammalian foetus an important end-product of meta- 
bolism is a diureide — allantoin — is a further proof of the close 
affinity of the tissue changes throughout the vertebrate series. 
Nor is this allantoin merely a product of foetal metabolism, for it 
has been found in small quantities in the urine of nearly all adult 
mammals in which it has been tested for. It was found in the 
urine of adult man by Ziegler and Hermann (1), and in that of 
cats, dogs, and rabbits, by Meissner (2). Pouchet (3) also found 
it in the urine of man, and in greater amount in the urine of 
pregnant women, as well as in diabetes insipidus and convulsive 
hysteria. Salkowski (4) found it in the urine of the ox to the extent 
of 0775 grm. per 1000 c.cm. 
I have found it in the urine of a rabbit to the extent of 0*14 per 
cent., and in the dog, upon a diet of oatmeal and milk, I have 
found, by the method afterwards to be described, the following 
amounts : — 
Per cent. 
0T1 grm. 
0*10 „ 
0-05 „ 
0-06 „ 
3 3 
Average, 0'08 
