From what has been said, it is obvious that the cause of a sore back can only be determined by seeing the saddle on. It is most desirable that the saddling should be done by the man who rides the horse, for in that way we are more likely to see matters as they occurred

Principles of fitting pack saddles
The general principles of fitting a pack saddle differ very slightly from that of the horse; the spine must be entirely free from pressure, the saddle must bear on top of the ribs, the side bars should not rest on the loins or the blade-bones, though for obvious reasons more of this is permissible in the mule than in the horse and pony. The load should be kept as steady as possible, for which reason two girths at a little distance apart keep the saddle firmly in its place.

The thick wither of the mule is frequently a difficulty, the arch of the saddle in many cases not being sufficiently wide to admit the panels without the withers getting squeezed. In fitting packsaddles this is one of the essential features to attend to, and the one which most frequently is found defective.

Of equal importance with a good wide front arch is a pair of well-stuffed panels. The amount of stuffing depends on the amount of muscle on the back, but assuming the back is well and liberally clothed with flesh the panels still need well stuffing, as their function is not only to prevent the back from getting bruised but to endeavour to convert a dead weight into an elastic one.

The length of the back from the pit of the shoulder to a hand’s breadth in the front of the point of the hip should be the length of the bearing surface of the panel. More than this is harmful.

If a pack saddle is (1) wide in the front arch and sufficiently high, (2) with panels stuffed to correspond with the length of the back, and (3) thick enough to form an elastic bed, then this is all the fitting required.