FURTHER PROOF OF THE EXISTENCE OF A SPECIFIC 



TETANY-PRODUCING SUBSTANCE IN THE 



THYMUS GLAND. 



By EDUARD UHLENHUTH. 



{From the Lahoratories of The Rockefeller Institute for Medical Research) 



(Received for publication, July 8, 1918.) 



In the preceding note^ it has been shown that salamander larvae which 

 are fed exclusively on calf's thymus gland develop tetanic convulsions. 

 Several facts were mentioned supporting the idea that this phenomenon 

 is identical with the tetany observed in mammals after parathyroid- 

 ectomy; it was also made probable by our experiments that the 

 tetanic convulsions, produced in the salamander larvae, were due to 

 the action of a specific substance contained in the thymus, inasmuch 

 as the thymus feeding did not become effective until the primordial 

 thymus glands of the larvae had reached a stage in which they assume 

 some of the structures of true thymus glands. 



Instead of assuming that the thymus gland secretes a toxin causing 

 tetany, it might be argued that the effects of thymus feeding were due 

 to the absence from the thymus ot some substances which are neces- 

 sary to make up a complete diet for the salamander larvae, for in the 

 experiments reported in our previous paper the larvae were fed exclu- 

 sively on thymus. In other words, it might be argued that the tetany 

 produced in our experiments was in reality a deficiency phenomenon. 



While formerly it was generally assumed that the thymus belongs 

 to the glands with internal secretion, doubts have recently arisen in 

 this regard. After it had apparently been demonstrated by some 

 authors that the thymus contains substances which stimulate the 

 growth of tadpoles of frogs and toads- in a specific way, Swingle^ has 



lUhlenhuth, E., /. Gen. Physiol, 1918, i, 23. 

 • 2 Gudernatsch, J. F., Arch. Entwcklngsmechn. Organ., 1913, xxxv, 457; Am. J. 

 Anat., 1913-14, xv, 431. 



3 Swingle, W. W., /. Exp. ZooL, 1917-18, xxiv, 521. 



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