36 TETANY-PRODUCING SUBSTANCE IN THYMUS GLAND 



substances in the thymus, we should expect that upon addition of a 

 complete diet to the thymus food tetany would still occur, but meta- 

 morphosis would take place in the normal way and at the normal time. 

 In fact, metamorphosis started even a few days earlier than in a con- 

 trol series consisting of thirty larvaj of the same age. Thus by adding 

 normal food to the thymus diet the specific actions of the thymus may 

 be sifted out from the non-specific ones. 



The tetany produced by exclusive thymus feeding is a specific effect 

 of the thymus due to the existence of a tetany-producing poison in 

 that gland, while the retardation of metamorphosis in the case of an 

 exclusive diet of thymus is due to a deficiency in the diet. 



CONCLUSIONS AND SUMMARY. 



The effect of the thymus gland in producing tetany is due to a 

 specific tetany toxin produced by and contained in the thymus, and 

 the thymus gland must be added to the group of glands for which the 

 function of internal secretion has been demonstrated. 



