PARATHYROID GLANDS 635 



from guanosin, a nucleoside, which in turn is derived from the extranuclear 

 mon-onucleotide known as guanylic acid. 



Though the proof has not yet been brought that either xanthin or 

 guanin is actually concerned in the production of the tetany intoxication, 

 the possibility of the participation of one or of both substances in the 

 process must, for the present, be kept in mind. 



Inosinic Acid. Inosinic ateid, an extranuclear mononucleotide, is a 

 forerunner of hypoxanthin. Greenwald for a time thought that inosinic 

 acid might be a cause of tetany, but later abandoned the idea. 



Phosphoric Acid. Phosphoric acid may be derived from nucleic acid, 

 but it has also other sources within the organism. Greenwald (&) (1916) 

 reported that the diminished excretion of phosphorus is the most striking 

 alteration of metabolism after para thy roidectomy, and suggested that a 

 search for the form in which phosphorus is retained might throw some light 

 upon the functions of the parathyroid glands. 



Carbohydrate Metabolism in Tetany 



In the literature of tetany several reports upon disturbances of carbo- 

 hydrate metabolism can be found. Thus, Eppinger, Falta, and Riidinger 

 state that, in dogs deprived of their parathyroid glands, the glycosuric ef- 

 fect of epinephrin is increased, provided that the injection does not cause a 

 general tetany spasm. Falta and Kahn have reported that, in human 

 tetany, in the acute stage, they had never observed glycosuria after injec- 

 tions of epinephrin, though the epinephrin did cause an essential increase 

 of the reaction of the cardiovascular apparatus. They thought that this 

 dissociation of the epinephrin effect, was due to several factors, most 

 notable, perhaps, the increase of the use of sugar through the enormous 

 vascular constriction that it produces. After the tetany had subsided they 

 were able often to demonstrate a distinct glycosuric effect on epinephrin 

 injection. 



In tetany in dogs, Eppinger, Falta, and Riidinger found the assimi- 

 lation limit for glucose constantly depressed, though in tetany in man, 

 tested by frequent examinations, this was not observable. 



Marine (1914) found that removal of the parathyroid glands in dogs 

 immediately lowered the alimentary tolerance for sugar, though rarely to 

 the degree of constant glycosuria. 



The total metabolism seems, in the acute stage of tetany, to be markedly 

 increased. Studies of total metabolism should also be made in chronic 

 tetany on account of the cachexia that develops in that condition. In gen- 

 eral, it may be assumed that there is an increased mobilization and com- 

 bustion of carbohydrates in tetany with increased heat production, though 

 in favor of a contrary view Watanabe (1918) found a decrease in the blood 



