376 CHYLE, LYMPH, TKANSUDATES AND EXUDATES. 



of BAUMANN and Roos that the active substance is iodoihyrin, as this 

 can be produced as a cleavage product from the iodothyreoglobulin. In 

 fact OSWALD has found in the tryptic digestion of iodothyreoglobulin 

 that a substance similar to iodothyrin is produced; important inves- 

 tigations 1 nevertheless make it probable that the thyreoglobulin is 

 the active substance and not the iodothyrin. There are several reasons 

 why the action of the thyroid gland substance is not due to one substance, 

 but to several. 



Iodothyrin is considered by BAUMANN, who first showed that the thyroid con- 

 tained iodine and who with Roos 2 proved the importance of this substance for the 

 physiological activity of the gland, as the only active substance. By boiling the 

 finely divided gland with dilute sulphuric acid BAUMANN obtained iodothyrin 

 as an amorphous, brown mass, nearly insoluble in water but readily soluble in 

 alkali and precipitated again by the addition of acid. The iodothyrin, which 

 is not a unit body, has a variable content of iodine and is not a protein substance. 

 According to v. FURTH and SCHWARZ it is probably a melanoid-like transforma- 

 tion product of the iodized protein of the gland produced by the action of the 

 acid. 



Thyreoglobulin or iodothyreoglobulin was obtained by OSWALD from 

 the watery extract of the gland by half saturating with ammonium sul- 

 phate. It has the properties of the globulins and with the exception of 

 the iodine content it has about the same composition as the proteins. 

 The amount of iodine varies: 0.46 per cent in pigs, 0.86 per cent in oxen, 

 and 0.34 per cent in man. In the iodothyreoglobulin of the ox, NUREM- 

 BERG 3 found 0.59-0.86 per cent iodine and 1.83-2.0 per cent sulphur. 

 In young animals, whose glands contain no iodine, the thyreoglobulin 

 is iodine-free. Thyreoglobulin on taking up iodine is converted into 

 iodothyreoglobulin. By introducing iodine salts the iodine content of the 

 iodothyreoglobulin can be raised in living animals and thus the physiological 

 activity increased (OSWALD). The amount of iodine in the gland is 

 markedly dependent upon the food. 



JOLIN has examined a large number of thyroid glands from healthy and 

 diseased persons (in SWEDEN), for their iodine content. In 28 children, ages 



1 See Oswald. Arch. f. exp. Path. u. Pharm., 60; Pick and Pineles, Zeitschr. f . 

 exp. Path. u. Therap., 7. 



2 In regard to this subject, see Baumann and Roos, Zeitschr. f. physiol. Chem., 21 

 and 22; also Baumann, Munch, med. Wochenschr., 1896; Baumann and Goldmann, 

 ibid.] Roos., ibid.', v. Fiirth and Schwarz, Pfliiger's Arch., 124. An extensive review 

 of the literature on the action of iodothyrin and the thyroid preparations can be found 

 in Roos, Zeitschr. f. physiol. Chem., 22, 18. In regard to their action in protein catabo- 

 lism and in metabolism, see F. Voit, Zeitschr. f. Biologie, 35; Schondorff, Pliiger's Arch., 

 67, and Andersson and Bergman, Skand. Arch. f. Physiol., 8; Magnus-Levy, Zeitschr. 

 f. klin. Med., 32. In regard to the function of the thyroid gland see also Sw. Vincent, 

 Innere Sekretion etc. Ergebnisse d. Physiol., 11, 218-302. 



3 Bioch. Zeitschr., 16. 



