THE BIOCHEMISTRY OF THE THYEOID GLAND 261 



on a dog, obtained a fall in weight, a rise in nitrogen excretion, and a 

 doubtful rise in phosphorus excretion. Treupel obtained similar results in 

 a case of myxede>ma, and with rabbits. (Of. also Grawitz, v. Vamossy and 

 Vas). Magnus-Levy stated that iodothyrin has as great an effect on the 

 respiratory quotient as has thyroid. Hennig did not get constant positive 

 results with goiter. Barbera found that the physiological effects of iodo- 

 thyrin are not the same as those of iodin or iodids. Asher and Flack found 

 that they are not the same as those of thyroid. Falta (a) found that the 

 physiological action of iodothyrin is much less than that of dried thyroid 

 substance. 



While different methods of preparation may account for part of this 

 total lack of uniformity, it would seem certain that if iodothyrin does 

 possess some physiological and metabolic activity, it does so to a very much 

 less extent than thyroid itself. 



Cyon and Oswald found that iodin-containing peptones and proteoses 

 derived from thyroid have no thyroid action on blood pressure and heart 

 beat, and do not possess the physiological properties of iodothyrin. Asher 

 and Abelin (1917) have examined "Thyreo-glandol-Roche," a thyroid 

 preparation soluble in water, free from protein, and containing little iodin, 

 and stated that it exerted the same physiological and metabolic effects as 

 the whole gland. Eiger (1917) obtained similar results with a liquid 

 obtained by perfusing the gland with Ringer's solution, and free from 

 protein, iodin, and cholin. According to Strouse and Voegtlin diiodoty- 

 rosin has no similar metabolic or physiological effect to thyroid, and no 

 curative effect on myxedema and cretinism. 



Iodothyroglobulin. Oswald (1899) quotes Magnus-Levy as authority 

 for the cure of myxedema by iodothyroglobulin. Administration to a dog 

 increased the nitrogen excretion, while the phosphorus containing nucleo- 

 protein had no effect (Oswald, 1902, Courvoisier and Lanz). It has the 

 specific thyroid effect on blood pressure and pulse (Oswald, 1901). Pick 

 and Pineles, using the effect on cachexia thyreopriva as a test, find that 

 iodothyroglobulin resembles thyroid, and iodothyrin does not. More 

 recently, Oswald (i) (1916) has studied the physiological properties more 

 exactly. lodothyroglobulin and its methylene derivative closely resemble 

 thyroid. Iodothyrin, gorgonin, and spongin show similar but weaker 

 activity, iodocasein, iodotyrosin, and thyroid nucleoprotein no effect. 



Thyroxin. Kendall (h) (1919) finds physiological effects after injec- 

 tion of thyroxin similar to those of thyroid. Heavy single doses are not 

 fatal, while continued smaller doses prove fatal (goats). Thyroxin in- 

 creases the basal metabolic rate. Plummer has shown that 1 mg. given an 

 adult weighing 150 Ibs. increases the rate 2 per cent, Kendall considers 

 that thyroxin acts as a catalyst, the activity being due to the CO-NH group. 

 It relieves all the symptoms of cretinism and myxedema to the same extent 

 as does desiccated thyroid (1918). Janney (a) found that with normal in- 



