PHYSIOLOGICAL PROPERTIES OF GONADS 385 



unquestionable. And also the external genitals of the female are 

 capable of modification as the result of the growth of a testicle 

 graft in a spayed female. Steinach was first to point out this 

 modification, and Lipschiitz had described the modification 

 wrought in the case of one of Steinach's animals. The clitoris 

 becomes hypertrophied until the configuration resembles a penis- 

 like structure, and the appearance of the genitals as a whole re- 

 semble the condition of the male animal more than that of the 

 female. Aside from these two modifications, there are no features 

 of a somatic nature that the writer can use as sex differentials. 

 A priori, if the weight of a normal female is less than that of the 

 normal male, and spaying results in a relative increase in weight 

 of the female (as is the case in rats), one would naturally assume 

 that a growing ovary in the male would relatively reduce its 

 weight. It may be possible that such is the case, but for this 

 character to be of any use as a sex differential would necessitate 

 a great number of cases in which a good ovarian graft was present. 



The weight of different individuals of the same age is such a 

 variable quantity that random comparisons are of no value. If 

 the weight conditions in guinea-pigs are comparable to those of 

 rats, we know that the presence of a testicle or testicle graft 

 would have no influence on the weight of the animal. Yet 

 Steinach and Holzknecht ('17) publish a table of weights of three 

 guinea-pigs (norm, female 845 grams, norm, male 1002 grams, 

 masculinized female 1200 grams) which indicates that not only 

 did the testicle graft cause a relative increase in weight of the 

 female, but the female became more of a male than the normal 

 male itself. Likewise, another table of weights (norm, male 980 

 grams, norm, female 808 grams, femininized male 516 grams) 

 indicates that an ovarian graft changes a male into an animal 

 more feminine than the normal female. The writer is inchned 

 to consider such a condition as very confusing and to discredit 

 the data as evidence of sex-gland activity. 



Many difficulties are involved in an intelligent anaylsis of the 

 psychical nature of animals and there is very great danger of the 

 personal equation influencing an interpretion. On the male side 

 the animal is always aggressive when strange animals are intro- 



