444 SUMMARY OF CURRENT RESEARCHES RELATING TO 



set over the other falls below a certain minimum, intersexual forms 

 result. 



Some of the intersexual females are very remarkable, with the 

 secondary sex-characters almost male, with instincts and behaviour inter- 

 mediate, with external genital organs showing the strangest combina- 

 tions, with typical but rudimentary ovaries. Others are externally 

 almost indistinguishable from true males, but certain characters, espe- 

 cially in the copulatory organs, still show their female origin. The sex- 

 instincts are entirely male. The gonad is like a testis, but shows in 

 sections every single step between an ovary with nothing but immature 

 eggs, through a mixture of ovarial and testicular tissue, to a real testis. 

 This is the highest grade of intersexuality that can be reached. The 

 next step would be the complete transformation of the would-be females 

 into males. And by other crosses this is also obtainable. All this 

 points to a quantitative conception of sex-determination. 



The series of intersexual males extends almost to femaleness. In low 

 grades the testis always contains some ovarial tissue. The highest grade, 

 of almost female exterior, contained a paired gonad (the normal ripe 

 testis is unpaired) of somewhat testis-like character, filled with giant 

 bundles of apyrene spermatozoa, and containing no eggs. 



Effect of Calcium Salts on Growth.* — Raymond Pearl gave grow- 

 ing chicks (29 to 171 days old) small daily doses of calcium lactate 

 or of calcium lacto-phosphate. Male chicks were not affected ; female 

 chicks showed marked increase (especially in lacto-phosphate treatment) 

 in the absolute amount of growth, and a corresponding acceleration in 

 the rate of growth. The reproductive organs of the females were 

 stimulated as well as growth. The rate of egg-production per unit of 

 time in the female chicks dosed with lacto-phosphate was nearly five 

 times as great as in the controls. If a small dose of corpus luteum 

 substance be administered along with the calcium lacto-phosphate, the 

 stimulating effect of the latter upon the growth of the females is com- 

 pletely inhibited. 



Various gland substances have a differential effect on the growth of 

 the two sexes. It is now shown that inorganic salts may have a 

 differential effect. This furnishes one more piece of evidence of the 

 deep-seated biochemical differences which underlie sex-differences. The 

 experiments are also in line with others whfch show the importance of 

 calcium in the physiology of the reproductive organs of the female. 



Influence of Pituitary Feeding on Growth and Sex Development, f 

 Emil Groetsch has experimented with rats, and finds that pituitary 

 extract (anterior lobe), given in food to young rats, has a stimulating 

 effect upon the growth of the animal and upon its sexual development 

 and activity. Posterior-lobe extract, when thus given, has a retarding 

 influence. Ovarian extract (corpus luteum) has a stimulating influence 



* ScieDce, xliv. (1916) pp. 687-8. 



t Bull. Johns Hopkins Hospital, xxvii. (1916) pp. 29-50 (4 pis.). 



