AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, JANUARY 19 
IS THE INFLUENCE OF THYMUS FEEDING UPON 
DEVELOPMENT, METAMORPHOSIS AND GROWTH 
DUE TO A SPECIFIC ACTION OF THAT GLAND? 
EDUARD UHLENHUTH 
The Rockefeller Institute of Medical Research, New York City 
The experiments on thymus feeding thus far reported in the 
literature have given results sufficieritly different to prevent the 
formation of a definite idea as to the réle of the organ in these 
experiments. This is even true if one has in mind only one of the 
various groups of animals which have been studied in such 
experiments. Concerning the Amphibia among which only the 
larvae of Anura have been studied carefully regarding their 
reaction to thymus feeding, it seems that most of the experiments 
showed a retarding influence of the thymus upon development 
and metamorphosis although some exceptions are reported. 
With respect to growth however, the results are so lacking in 
uniformity, that Gudernatsch as well as Romeis who studied the 
effect of thymus feeding in tadpoles doubted whether the effect 
produced by this organ was due to a specific action or only to 
quantitative conditions. Gudernatsch in his experiments on 
tadpoles noted accelerated growth leading to enormous size; 
but Romeis obtained completely normal growth in various series 
of thymus-fed tadpoles and pointed out that the thymus feed- 
ing never produces abnormally large animals. 
The following experiments which will be reported elsewhere 
in detail, seem to indicate that the accelerated growth of thy- 
mus fed Amphibian larvae is merely the effect of quantitative 
conditions and not the result of a specific quality of the organ 
such as a specific growth-stimulating agent. Furthermore, they 
yielded some very interesting results concerning development 
and metamorphosis although these are still difficult to explain. 
Finally they showed that in each thymus-fed larva severe tetany 
135 
