638 ANATOMY AND PHYSIOLOGY OF THE HORSE’s FOOT. 
tive powers, that the remarkable networks of vessels which 
cover the organ everywhere have been devised. 
This exaggerated vitality, consequent upon the great 
quantity of blood directed to these membranes, is not 
brought so prominently into notice while the foot is in a 
healthy condition as when its circulation has been disturbed 
or deranged from some cause, and congestion or inflamma- 
tion results. Then the intense vital energy with which the 
living portions of the foot are endowed is manifested in the 
most unmistakable manner by the rapidity with which the 
various phenomena peculiar to these conditions are developed 
and extended, and pass through their several phases, implica- 
ting more or less of the organ in a very brief space, giving 
rise only too frequently to very serious consequences and the 
gravest pathological alterations, which nothing but the most 
prompt and skilful surgical treatment can avert, palliate, or 
cure. 
The exalted vascularity and vitality which is so conspicuous 
in this organ have doubtless been conferred to enable it to 
meet the excessive demands to which, during life, it is 
subjected ; demands which are incurred either through the 
various movements and fatiguing strain to which it is 
exposed, and which entail renovation and repair of texture, or 
those arising from the constant wear of the horny case pro- 
tecting it, and which must be anticipated by an uninterrupted 
secretion* of the dense material of which that protection is 
composed. 
It has been observed that the hoof is a most essential part 
of the horse’s foot, and fulfils its office in a perfect manner 
through the combination of certain conditions, some of which 
are apparently incompatible with each other — such as elas- 
ticity and rigidity, solidity and suppleness, durability and 
lightness. The qualities which the hoof possesses in so 
marked a degree would soon become deteriorated or destroyed 
by the incessant attrition to which it is exposed between the 
ground and the column of support, as well as by the influ- 
ence of other and less discernible causes, were they not 
always maintained intact by the activity of the living tissues 
* I have used the word “ secretion ” in this place, perhaps, for lack of a 
better term, and also because it is that most frequently employed to desig- 
nate the generation of the horn. Strictly speaking, however, it is not a 
correct word to apply to the keratogenous process, as this is no more a 
secretory function of the living textures of the foot than is the production 
of the epiderm of the derm. When, therefore, the “ secretion” of horn is 
spoken of, it will be understood that the transudation or formation of that 
material from the surface of the vascular membrane is meant, and not an 
actual secreting process. 
