We have shown that no living tissue can stand continuous pressure, not even when a relatively soft and light body is inflicting it, let alone a mechanism of steel and wood like a saddle tree.

That a certain power of resistance to both friction and pressure exists is undoubted; a horse in hard conditions can stand much more of either than one in soft condition.

Bearing of condition on injuries
The evil of soft condition is more readily shown by friction than by pressure. It is remarkable how little friction the soft horse can tolerate.

The tolerance of both friction and pressure is characteristic of the horse in hard condition, and we see the same in the well-trained man, who is very difficult to bruise.

Condition enormously influences the production of sore backs, and condition that may be of three kinds:

 1. Hard condition, such as we meet with in the full-fed, hard-worked horse.

 2. Poor condition such as is met with in the horse under-fed and over-worked.

 3. Soft condition, well seen in the fat horse who has done no work.

No. 1 takes a lot of friction and much pressure, but Nos.2 and 3, though at opposite poles, behave as if identical. In No.2 the vitality and resisting power lowered through hard work and insufficient food; in No.3 there is a good deal of vitality, but of a fluid kind, it soon evaporates, while of resisting power there is none.