202 Thyroid and Liver Glycogen 
mal blood containing only 7.13 mg.). Many cleavage products 
of protein, such as amino-acids, creatine, creatinine, and others, 
have been reported to accelerate the activity of the diastase.* 
Though the liver and blood of thyroid-fed animals do not show 
any increased diastase content, it may be possible that some 
substances, which are produced to an abnormally large degree, 
on account of an increase of metabolism, accelerate the activity 
of diastase within the living cells. 
The Influence of Thyroid Feeding upon the Glycogen Content of the 
Liver of Full Grown Frogs. 
Determining the glycogen content of the frog (Rana fusca) at different 
seasons, Athansiu®* reported that the glycogen content of the frog body 
is lowest in the summer, at which time they take the most nourishment, 
and the highest in the fall, gradually decreasing in the winter. At the end 
of hibernation the body still contains a large amount of glycogen. This 
statement was confirmed in general by Pfliger.3’7 In frogs, glycosuria 
can be induced by subcutaneous application of phlorhizin, but not by 
oral administration.3® Scaffidi?® reported that phosphorus poisoning in- 
duces a marked loss of the liver glycogen of frogs (Rana esculenta) in a 
short time. Mangold,*® however, observed that after the long continued 
convulsions caused by strychnine, which promptly reduce the liver gly- 
cogen of warm-blooded animals, the liver of a frog still contained a large 
amount of glycogen. As shown by Gudernatsch,*® Lenhart,*! and Gra- 
ham,” thyroid feeding exerts a remarkable influence upon the growth 
of tadpoles. Emaciation, retardation in gain of body weight, and early 
differentiation of body parts can be noticed in a few days. Lenhart con- 
siders that the effect of thyroid feeding is closely associated with both the | 
iodine content of thyroid and tae amount fed. 
In full grown frogs, the metabolism is probably most active 
in the summer time. It may be interesting to know whether in 
this season thyroid feeding of full grown frogs can increase the 
metabolism or at least cause any decrease of the glycogen con- 
$5 Hffront, J., Compt. rend. Soc. biol., 1904, lvii, 234. Terroine, E. F., 
and Weill, J., J. physiol. et path. gen., 1912, xiv, 437. 
86 Athansiu, J., Arch. ges. Physiol., 1899, lxxiv, 561. 
37 Pfliiger, E., Arch. ges. Physiol., 1907, cxx, 253. 
#8 Lusk, G., Hrgebn. Physiol., 1912, xii, 315. 
39 Mangold, E., Arch. ges. Physiol., 1907-08, cxxi, 309. 
40 Gudernatsch, J. F., Am. J. Physiol., 1914-15, xxxvi, 370. 
41 Lenhart, C. H., J. Exp. Med., 1915, xxii, 739. 
“ Graham, A., J. Exp. Med., 1916, xxiv, 345. 
