356 CHYLE, LYMPH, TRANSUDATES AND EXUDATES. 



is also considered as a form of hyperthyreoidismus which, by an increased 

 activity of the glands, brings about an overproduction of the specific 

 secretion. 



It is impossible for the present to state anything about the kind of 

 bodies here, having a specific action or anything about the importance of 

 the bases found by certain investigators, such as S. FRANKEL, DRECHSEL, 

 and KocHER 1 ; these bodies have not been characterized sufficiently. It 

 seems proven that the specifically active substance is, as first shown 

 by NoTKiN 2 and OSWALD, 3 a protein substance: NOTKIN'S thyreoproteid, 

 OSWALD'S thyreoglobulin. This does not conflict with the views of 

 BAUMANN and Roos that the active substance is iodothyrin, as this can 

 be produced as a cleavage product from the iodothyreoglobulin. In 

 fact OSWALD 4 has found in the tryptic digestion of iodothyreoglobulin 

 that a substance similar to iodothyrin is produced; for several reasons it 

 seems that 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 5 proved the importance of this substance for the 

 physiological activity of the gland, as the only active substance. By boiimg 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 transfor- 

 mation 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 sulphate. 

 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 



1 Frankel, Wien. med. Blatter, 1895 and 1896; Drechsel and Kocher, Centralbl. 

 f. Physiol., 9, 705. 



2 Wien. med. Wochenschr., 1895, and Virchow's Arch., 144, Suppl., 224. 



3 Zeitschr. f . physiol. Chem., 32, and Bioch. GentralbL, 1, 249. 



4 Arch, f . exp. Path. u. Pharm., 60. 



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

 #nd 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 destruc- 

 tion and metabolism, see F. Voit, Zeitschr. f. Biologie, 35; Schondorff, Pfliiger's Arch., 

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

 f. klin. Med., 32. 



