974 



SGIENGE. 



LN. S. Vol. V. No. 130. 



The negative results obtained by Gottlieb * 

 have been recently shown to be due to the 

 employment of a poor preparation. 



Does the physiological action of the thy- 

 roid gland reside wholly in this so-called 

 iodothyrin or its antecedent ? In attempt- 

 ing to answer this question we must give a 

 moment's attention to Frankel's so-called 

 thyreoantitoxin. f This, as you may remem- 

 ber, is a crystalline body of neutral reac- 

 tion obtainid from the proteid-free extracts 

 of the thyroid gland. It is soluble in 

 water and alcohol, but precipitable by ether 

 and acetone, and from its composition it has 

 been suggested that it is a guanidiu deriva- 

 tive. Friinkel ascribed to this substance 

 the physiological activity of the thyroid 

 gland, since he obtained a suspension of 

 convulsions with thyroidectomized cats on 

 injecting this body. Fiirther, DrechselJ 

 has made a preliminary communication to 

 the effect that the proteid-free extract of the 

 thyroid from pigs contains two crystalline 

 substances in small amount, which when 

 fed to thyroidectomized animals appear 

 somewhat active, although not strongly so. 

 Drechsel therefore suggests that possibly 

 there may be three active substances present 

 in the thyroid, viz, two bases, one identical 

 with Frankel's antitoxin, and Baumann's 

 iodothyrin. He would thus ascribe to the 

 thyroid several associated functions and 

 corresponding to each a distinct chemical 

 substance. Theoretically, of course, this is 

 quite plausible, but Drechsel's compounds 

 have not been further heard from and there 

 are many recent observers who fail to find 

 any physiological action whatever with the 

 proteid-free extract from the gland. § More- 

 over, careful comparative study of the ae- 



*DeutBcli. med. Wochensohr., 1896, No. 15. 



t Wiener klin. Wochensohr., 1895, No. 48. 



X Die Wirksame Substanz der . Sohilddruse, Vor- 

 laufige Notiz. Centralbl f. Physiol. Band 9, p. 705. 



§ See Hutchinson : The chemistry of the Thyroid 

 Gland and the nature of its active constituent. Jour- 

 nal of Physiol., Vol. 20, p. 491. 



tion of thyreoantitoxin and iodothyrin in a 

 myxoedema patient showed that while the 

 former was entirely without beneficial ac- 

 tion the latter produced all the results 

 characteristic of thyroid feeding. * Further, 

 Roos, t by experiment on a normal dog in ni- 

 trogenous equilibrium, found that thyreoan- 

 titoxin was wholly without influence on me- 

 tabolism, while iodothyrin given to the same 

 animal under like conditions caused at once 

 a marked increase in the output of nitrogen, 

 NaCl and P^Oj. In other words, thyreo- 

 antitoxin shows with certainty none of the 

 properties of the thyroid gland, while iodo- 

 thyrin is apparently the physiological 

 equivalent of the gland. Indeed, in its ac- 

 tion on goitre iodothyrin is more effective 

 than the gland itself, since when the gland 

 is taken it must first undergo digestion to 

 liberate the iodothyrin and some may be 

 lost by putrefactive changes in the intestine. 

 What now is the significance of the 

 iodine contained in the so-called iodothyrin? 

 Iodine is not a common constituent of the 

 animal body, and its discovery by Baumann 

 in the thyroid gland toward the end of 1895 

 was the first intimation of its presence in 

 the human organism. So far as known, it is 

 not normally present to any extent in other 

 tissues. J Traces, however, are found in the 

 thymus of the calf (Baumann). § Barrell 

 has likewise reported the presence of traces 

 in the spleen, adrenals and the ovaries of 

 pigs and cows. The amount, however, is very 

 small as compared with that found in the 

 thyroid. Calling the amount of iodine in 1 

 gram of fresh thyroid as 1, the spleen con- 

 tains -^-^, the adrenals -^l-^, and the ovaries 



* Magnus Levy: Deutsche med. Wochensohr., 

 1896, No. 31. 



fMiinchener med. Wochensohr. 1896. No. 47. 



JDrechsel has reported finding a distinct trace of 

 iodine in the hair of a syphilitic patient treated for a 

 longtime -with postasium iodide. Centralbl. f. Physiol. 

 Band 9, p. 704. 



gVorkommeu von Jod in den Ovarien. Chemisches 

 Centralblatt, 1897. Band 1, p. 608. 



