SEX SPECIFIC ACTION OF HORMONES 299 



woiild be an. action similar to that on the sexual reflexes. I 

 should state, however, that I lost confidence in my own 

 measurements on the guinea pig after Bormann, Brunnow and 

 Savary (1923, see also Lipschiitz, 1923 a) in our Institute 

 repeated these experiments on the rabbit. In their experi- 

 ments, performed with great care, there was no difference 

 between the normal male and female; there was also no 

 difference between the castrated and the normal female; 

 Bormann and Brunnow examined rabbits of different ages, 

 as I thought that possibly the sex difference in body tempera- 

 ture would become more pronounced after full sexual maturity 

 was attained. But they found subsequently no difference 

 between male and female in animals of full sexual maturity. 

 The animals were as far as possible of the same litter. Recently 

 Ocaranza (1922) stated that there is no difference in the body 

 temperature of male and female guinea pigs. Steinach's 

 and my conclusions derived from records on the guinea pig 

 are erroneous. Evidently the number of our records was not 

 sufficient, and the individual variation was too great. As 

 Brunnow and Bormann showed, the result of the reading 

 depends largely on technical details, especially on the position 

 of the animal at the time of measurements, and on the depth 

 to which the thermometer is introduced into the rectum. 



(b) Masculinization, 



Steinach (19 13) performed experiments with implantation 

 also of testicle into castrated female rats and guinea pigs. 

 The number of successful experiments was very small, but 

 wholly sufficient for demonstrating the sex specific action of 

 the testicle in the body of a female. In one experiment the 

 testicular graft remained in a female guinea pig for more than 

 three years, i.e., as long as some ovarian grafts in the male 

 organism {Steinach, 1916). Similar experiments were afterwards 

 recorded by Sand (1918, pp. 89-91); 'in guinea pigs the grafts 

 underwent resorption, whereas a number of experiments with 

 rats were successful. Successful experiments on the rat and 

 the guinea pig have been recorded also by Moore (1919 a, 1921). 



We have seen in the preceding section that the development 

 of the teats and mammary glands of the male is induced by 

 the ovarian graft. On the contrary the teats remain unde- 

 veloped rudimentary organs if a testicle is engrafted in a 



