PAKATHYEOID GLANDS 633 



(1) the total nitrogen is increased, (2) the ammonia ratio is increased 

 (MacCallum and Voegtlin), (3) the amino acid fraction is usually nor- 

 mal, whereas (4) the peptid nitrogen fraction is considerably increased 

 (Falta and Kahn). The increased output of peptid nitrogen, of total 

 nitrogen, and of ammonia nitrogen apparently can continue for some time 

 after the acute stage of tetany has passed. 



Toxic Substances of Protein Origin in Tetany. The possibility of the 

 accumulation within the body of certain poisons derived from protein, 

 especially from two of its constituent amino acids, histidin and arginin, 

 has been suggested by the studies of several investigators. 



Attention was drawn to histidin as the possible source of the tetany 

 poison by the fact that the phenomena of tetany are similar to those of 

 chronic ergotism (Fuchs (a)). The active principle of ergot seems to be 

 beta-imidazo'lyl-ethylamin ; and this substance is a derivative of one of the 

 amino acid building stones of protein, namely histidin, which is beta- 

 imidazol-alpha-amino-propionic acid : 



I should like to draw attention also to arginin,, on account of the studies 

 of Koch (a>) (&) and, later, of Paton and his collaborators. Koch found 

 certain amino bases (methylguanidin and trimethylamin) in the urine of 

 dogs suffering from experimental tetany, and Paton and his coworkers as- 

 sert that they can produce symptoms identical with those of tetany by the 

 injection of guanidin and its salts. One probable source of guanidin in 

 the body would, it seems to me, be the guanidino acid known as ar- 

 ginin, which is one of the diamino acids of the protein molecule. Arginin 

 is alpha-amino-delta-guanidino-valerianic acid having the formula 

 NH 2 -C (NH)-NH-CH 2 -CH 2 -CH 2 -CH.NH 2 -COOH. 



It may be that the further studies of these derivatives of histidin and 

 arginin may throw much light upon the true nature of the tetany poison, 

 though it is too early to be sure of this. 



Creatin is another amino acid that contains a guanidin group, for it 

 is methylguanidino-acetic acid, having the formula NH 2 -C(NH)- 

 N(CH 3 )-CH 2 -COOH. The anhydrid of creatin is known as creatinin, 

 and this substance is methyl-glyco-cyamidin. 



The guanidin of arginin is ordinarily converted in the body, through 

 hydrolysis, into urea and ornithin (Drechsel), probably through the in- 

 fluence of a ferment, arginase, discovered by KosseL Creatin and 

 creatinin could, in a similar way, have their guanidin groups changed into 

 urea by hydrolysis in the normal organism. Should the studies of Koch, 



