1910-11.] Bone Growth in absence of Functioning Testicles. 131 
Summary and Conclusions of Section I. 
Anatomical and Anthropological Investigation. 
The results of this anatomical and anthropological investigation may be 
summarised thus 
1. In the absence of functioning testicles, the process of endochondral 
ossification is stimulated and prolonged. 
2. The stimulation and prolongation do not affect the cartilages equally ; 
the distribution of the resulting growth is therefore not equal. 
Although the distribution of the growth is unequal, it is not fortuitous, 
but follows a uniform scheme of distribution in men and animals. The 
bones most markedly affected are the bones of the leg, next those of the 
forearm, then that of the thigh and the arm, then the limb girdles, and, last 
and least, the vertebral column, within the limits of which the distribution 
is again unequal, the thoracic regional segment being most affected. The 
skull is also affected. The cranial capacity develops less completely than is 
normal. The expansion of the antrum of Highmore, alone of the nasal 
system of air cells, is retarded. As a direct result of this, the face remains 
narrow and the nasal part of its height short. The alveolar process of the 
superior maxilla grows out of proportion to the rest of the bone, as also 
do the mandibular symphysis and coronoid process. 
4. These growth changes are clearly the result of an uncomplicated 
testicular failure, for they occur in otherwise healthy males if the testicles 
are removed by operation before the cartilages of the synchondroses are 
obliterated. 
5. In their general incidence, though not in their intensity, the growth 
changes resemble those found in giants, who may or may not be sterile, 
though such abnormal beings usually are sexually deficient. 
These are the mediate results of the absence of functioning sexual glands. 
It is clear that the immediate results of removal of the testicles must be 
twofold : — 
1. The constituents of the blood which normally provide for the nutri- 
ment of the testicles, and meet the demands of spermatogenesis, will no 
longer be required, and will become available for the use of the somatic cells. 
2. The waste products (internal secretion ?) of the testicles will no longer 
be thrown into the blood, and the nervous stimuli arising from the collection 
of semen in the seminal vesticles will no longer affect the organism. 
The somatic cells, under these circumstances, must experience a changed 
environment. An attempt to form some conception of the nature of that 
change forms the subject of the next section. 
