PHARMACOLOGY OF HYPOPHYSEAL EXTRACTS 743 



pound is soluble in ethyl alcohol, ether, chloroform and carbon tetra- 

 chlorid. Aqueous solutions are faintly acid. Tethelin contains 1.41 per 

 cent of phosphorus and 2.58 per cent of nitrogen. The aminonitrogen 

 content is 1.24 per cent and increases on hydrolysis. The compound has a 

 saponification value of about 87 mg. of KOH per gram of substance and 

 a mean iodin absorption value of 33.2 per cent. In aqueous solutions no 

 biuret reaction is given: the Millon reaction is atypical. It does not 

 reduce Fehling's solution either before or after hydrolysis with barium hy- 

 droxid or barium dioxid followed by sulphuric acid. It gives Ehrlich's 

 reaction indicating the presence of an acetylated oxyamino group. Wie- 

 del's reaction is positive, indicating the probable presence of an iminazolyl 

 radical. When tethelin is decomposed by mild hydrolysis inosite is found 

 among the products of the reaction. The occurrence of this compound as 

 a component of tethelin is particularly interesting from the fact that it is a 

 normal constituent of the rapidly growing parts of plants. 



Effects of "Tethelin" on Growth. Having obtained this compound 

 a,s an extract of the anterior lobe of the hypophysis Robertson(fr) (1916) 

 compared its effects on the growth of white mice with the effects produced 

 by feeding anterior lobe substance as a whole, and came to the conclusion 

 that "the effects of tethelin upon the growth of white mice resemble in 

 every particular the effects of the administration of the whole anterior 

 lobe." Later Robertson and Delprat (1917) found that tethelin when fed 

 to the mothers of suckling mice was apparently not secreted by the mam- 

 mary glands since the growth of the young was unaffected while suckling, 

 but when the compound was added to the diet of the animals at weaning 

 growth was immediately accelerated. 



A similar identity in the effect of the anterior lobe substance and 

 tethelin was observed when studies on the growth of carcinomata were 

 made. Robertson and Burnett (a-) (&) (1915) had found that the injec- 

 .tions of extracts or emulsions of the anterior lobe cause an increase in the 

 growth-rate of the primary tumor in rats inoculated with carcinoma at cer- 

 tain states, though no enhancement of metastatic tendency was observed. 

 When these same workers (1916) injected tethelin instead of the emulsions 

 of anterior lobe into carcinomatous rats a rapid growth of the primary 

 tumor was observed and the additional effect was produced of an increased 

 tendency to metastatic involvement. 



The attempts at correlating this growth-promoting effect of tethelin 

 with some specific group or radical of the compound have so far been un- 

 satisfactory, though Robertson and Burnett(c) (1918) have obtained evi- 

 dence pointing to the possibility that the presence of an hydroxyl group in 

 the molecule may be the effective point of attack. 



Although the evidence accumulated by Robertson and his coworkers 

 undoubtedly indicate that in tethelin there has been produced a substance 

 possessing the same growth-promoting functions in concentrated form as 



