272 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
reduction of the oxygen supply. In addition to the age-factor, which 
is most important, it seems that variations in the permeability of the 
eggshell to gases and the sex of the enclosed embryo are additional 
factors. J. A. T. 
Hen-feathering induced in Male Fowls.— B. Horning and H. B. 
Torrey ( Proc . Amer. Soc. Zool . in Anat. Record , 1922, 23 , 132). Fed 
daily with thyroid, in doses increasing with their weight, from the age of 
three weeks, Rhode Island Red chicks of male sex developed plumage 
of the female type, although males of this breed ordinarily do not pass 
through a juvenile stage characterized by plumage of the female type. 
The plumage of capons, usually ultra-male, is not affected. Castrated 
females which typically develop male plumage are similarly unaffected. 
The primary effect of the thyroid feeding seems to be to increase the 
activity of the “ lutear ” interstitial tissue of the testis. “ The end 
result is a hen-feathered male resembling in all essential characteristics 
of the plumage the hen -feathered male of the Seabright and Campine 
breeds.” J. A. T. 
Gynandromorph Fowl. — P. Murisier (Bull. Soc. Vaudoise Sci. 
Nat., 1921, 54 , 123-30, 1 fig.). A red Rhode Island fowl with 
somewhat cock-like characters in erectile organs and plumage, yet 
dominantly a hen. The ovary showed total degeneration as the result 
of a precocious tumour. In fact the animal had been pathologically 
castrated. J. A. T. 
Interstitial Cells in Testis of Guinea-pig. — A. Lipschutz, 
B. Ottow, C. Wagner and F. Bormann (Proc. Roy. Soc., Series B, 
Two sections through the testis of a normal gninea-pig aged 
about 4£ months. On the left, interstitial cells in form of a 
triangle between tubules in full spermatogenesis ; on the right, 
interstitial cells embedded in a granular mass in the neighbourhood 
of blood-vessels. 
1922, 93 , 132-42, 2 pis.). In experiments with partial castration 
small testicular fragments show enormous hypertrophy of the interstitial 
