66 



PIGMENTARY GROWTH AFTER ABLATION OF 



efTed has boon produced in normal larvae by such alimentary 



regimes. 



One article of diet, livor— the chief nutritive substance sup- 

 plied is common to the specimens of the second division. 

 That the retardation in the growth rate of these specimens is 

 not due to a growth-retarding substance in the liver, but to the 

 absence of the hypophysial growth-maintaining substance, is 

 clearly indicated by three lines of evidence: 1) we should have 



TABLE 5 

 Table giving the number <>j normal, ihyroidectomized, and albinous toad larvae on which 



the accompanying growth-curves arc based 



BUCCAL COMPONENT OF HYPOPHYSIS ABLATED 



THYROID 

 ABLATED 



NORMAL 



Liver 



diet 



DIET OF GLANDULAR LOBE OF HYPOPHYSIS 



Liver 



diet 



Glandu- 

 lar lobe 

 diet 



Fresh 

 glandu- 

 lar lobe 



Alco- 

 holic 

 extract 



f, Alco- 



., holic 

 residue 



Aqueous 



extract 



Aqueous 



residue 



Colloid 



18 

 18 

 

 



Killed accidentally. 



to likewise assume that such growth-retarding substances were 

 in adrenal cortex, adrenal medulla, and posterior lobe, for the 

 same growth delay exists when albinous larvae are fed with 

 any of these substances; 2) Mendel and Osborne ('18) have shown 

 that the proteins of liver are adequate for the needs of nutrition 

 in mammalian growth; 3) normal frog larvae supplied with a liver 

 diei exhibit an entirely normal rate of growth. 



It seems clear, then, that the normal growth rate of the al- 

 binous specimens receiving fresh anterior lobe or its residues is 

 due to an alimentary replacement of the growth-maintaining 



