118 EXAMINATION OF HORSES 
to be removed by absorption and ankylosed in the 
manner above described. I have no doubt that in 
the course of time—and here I refer to time as 
counted by the geologist rather than as counted by. 
the historian—these lower bones of the hock will 
‘become one and lose their light spongy texture, and a 
more perfect hock will result. J¢ és during this trans- 
Jormation stage that spavin is produced. All the parts 
are then more vascular and more susceptible to the 
effects produced by being pushed and pulled from here 
‘to there. Whenever we find a part changing the cha- 
racter of its life—whether it be from a lower-form to 
a higher, or from a higher to a lower form—we find in 
it extra activity of the parts whose office it is to build 
it up and to pull it down (the blood-vessels and the 
absorbents). And if these builders, and. carriers are 
unduly meddled with they at. once revolt. Let us take 
one striking example. Let us look at the mammary 
gland immediately its owner becomes a mother, and 
notice how the least extra excitement induces abscess 
‘in the generous gland, which is already in the full height 
of its activity. Then again look at the mammary gland 
and the uterus in womankind, how extremely prone 
these structures are to become the seat of cancer at the 
end of child-bearing, or, in other words, when the need 
for their activity is past, and when they are therefore. 
passing from a higher to a lower life. Of the several 
forms of exostosis to which we ourselves are liable, the 
one which is most like in its nature to splint occurs 
