20 



Scientific Proceedings (94). 



fections. An entirely satisfactory explanation for these low 

 values, however, is not apparent. This is a topic to which we 

 plan to give further study. 



With the method it is possible to demonstrate a considerable 

 decline in the activity of the saliva as a result of the glandular 

 fatigue produced by the continuous secretion of saliva during 

 paraffin chewing. Our results likewise indicate that the method 

 is a very suitable one to employ in demonstrating the diurnal 

 variation. 



14 (1389) 



Parathyroids and calcium metabolism. 



By E. Uhlenhuth. 



[From the Rockefeller Institute for Medical Research, New York 



City, N. Y.] 



Larvae of the salamanders Ambly stoma maculatum, Ambly stoma 

 opacum and Eurycea bislineata when fed on thymus exhibit severe 

 tetanic convulsions. In contradiction to other amphibian larvae 

 which do not show this reaction, they possess no parathyroids; 

 the tetanic convulsions of the thymus-fed salamanders are iden- 

 tical with a true parathyreoprival tetany. 



The tetanic action of the thymus is due to the presence in the 

 organ of the tetany toxin which can be antagonized only by the 

 parathyroids, but not by the substances contained in normal 

 food. The addition to the thymus diet of normal diet in amounts 

 sufficiently large to keep a salamander larva in a perfectly normal 

 condition does not prevent the tetanic convulsions. Tetany is 

 caused by a toxic substance contained and excreted by the thymus. 



Calcium salts, when dissolved in the water in which the 

 thymus-fed larvae live, do suppress, to some extent, the tetanic 

 convulsions. Magnesium salts, however, assert the same action 

 and are still more effective than calcium salts. The suppression 

 of the tetanic convulsions by the salts of calcium is not a specific 

 action of the calcium. 



Neither calcium nor magnesium is able to prevent the devel- 

 opment in the thymus-fed larvae of severe and permanent lesions 

 of the muscular system, lesions which are caused probably by 



