GONADS AS CONTROLLERS OF CHARACTERISTICS 157 
cells. Figure 5, a more highly magnified part of the graft from 
female 6, AIBI-II, shows the condition of the cells that remain 
within the tubules as well as the large number of cells between 
the tubules. The latter evidently represent the interstitial 
gland described by Steinach and supposed by him to be the seat 
of the production of the hormone of the testis. Between the 
tubules are usually to be found a great number of leucocytes 
scattered indefinitely throughout the tissue, but the significance 
of these is not entirely clear. 
The writer purposely refrains from an elaborate description 
of the cytological findings, as Steinach has discussed them ade- 
quately. The figures included will enable one to realize the 
condition of these pieces of transplanted gonads. 
DISCUSSION 
These observations corroborate parts of Steinach's experi- 
ments and tend to support very strongly his ideas of the trans- 
forming power of the gonad of one sex over, at least, the psychic 
nature of the opposite sex. While the writer is entirely unable 
to interpret the observations of the possible somatic differences 
of these evidently modified rats as a distinction of maleness and 
femaleness, nevertheless the psychic behavior of the animals, 
absolutely distinct in itself, lends great weight to the idea of a 
transformed sexual nature. 
On the somatic side the early spayed female rat With implanted 
testis increases in weight, but it has been shown that the testis 
has no influence upon growth, but that elimination of the ovary 
does allow a relative increase in weight; the same is also true in 
regard to body length. The presence of the ovary tends to re- 
tard the growth of the animals, either male or female, but it is 
very difficult if not impossible to interpret these changes intelli- 
gently in relation to a modified sexual condition. The testis 
is entirely without effect in this regard. 
Neither the hair coats, fat deposition, nor temperamental be- 
havior outside of sexual reactions and maternal instincts appears 
to the writer to be of any deciding significance, and the size of 
the pelvis and other bones, for reasons already given, appear at 
