described; and I find that it is its laminated attachment that constringes the wall internally.

It is whilst the greatest degree of pressure is being exerted on to the last bone, and whilst the extremity of the lever is being elevated posteriorly by uplifting powers that the arches, both of bone and sole, require all sustaining strength.

At this juncture there is a concentration of energetic force called into action in the pedal extremity, whilst the effect is that the weight is passed over the point of the lever. (See illustrations above, exhibiting the flexor pedal ligaments, on which force is exerted.) In the meantime the limb has been sustained by the upward and forward pressure of the posterior region of the foot. And it is in virtue of the connecting medium which the laminæ afford, and the recoiling round the cartilages as the hoof does, that the yielding posterior region compresses and sustains the anterior, and, by binding structures, concentrates strength.

The foot is compressed, instead of, as has been said, widening when pressure is conveyed on to it, and it dilates when lifted. And this applies not only to the foot of the horse, but holds good as a physiological law.

If the horse is put into a walk, movements such as have been described will take place. I cannot in this communication enter into more than a few details on 'Progression,' such as refer to the sequence, in which the limbs are moved in all the paces. My aim is more directed to the consideration of important questions on the general economy of the foot and movements of the limbs which produce progression.

The horse moves in the walk, as has been well described by ancient writers, and in recent years by Percivall and others, by lifting one foot at a time in regular succession. A fore foot is always first relieved and lifted, it may be left or right, according to the standing position at the instant.

It is not, as seems commonly thought, where thought is given to the matter, that in the movements of all four limbs so many different mandates from the will are given. One flash of life's electricity puts all in motion.

The lifting of the foot into the air, and even extending it, produces no movement. Thus, when draughtsmen represent a horse standing firmly on three legs, with one fore foot lifted and fully flexed, they represent the prevailing erroneous notions on the way movement takes place. An animal may lift one foot at a time, but will never move until the full action of all the limbs is exerted.

The body of an animal-I use the word generally, because it applies to every animal-always is moved before a foot is lifted. The direction in which action proceeds is from the great bony shafts forming the upper regions in connection with the trunk. Thus performing their steady strokes, these shafts set the knee and hock joints moving, and the levers which have their fixed parts on the ground are all at the same instant set in movement. A fore foot

is always the first to be lifted in the walk, and this takes place as the body passes over, when it is then flexed and extended. The opposite fore and its diagonal hind are at the instant the sustaining powers, while the diagonal hind of the fore first lifted is raised posteriorly, and is in the propelling attitude; which act done it passes on, its lateral fore being the third to move, whilst the first fore moved has alighted and its lateral hind has also moved. The action of the horse can be better learned by looking at the limbs in pairs, than by embarrassing the untrained eye and the senses with the task of following the action analytically of all four feet at once. The great powers which result through muscular energy, on angular shafts, which are acted on from above, and have their fulcra on the ground, take place in diagonal lines from each fore to its opposite hind; whilst there is equally a continued sequence of harmonising force going on between each lateral fore foot and its parallel hind. Thus perfect equilibrium of gravity in the body prevails. The way this action is produced, as most of my readers know well, is through the opening of the angles of the wonderfully constructed limbs, which as much surpass all machinery made by human hands as all Infinite works surpass man's conception. The action of the fore limbs always takes precedence of that of the hind. I reserve to myself hereafter to revert to the first move in the gallop, correctly given by Borelli, which does not alter the above proposition. In my former communication I stated, and also showed by a woodcut which has been reproduced in this, with an additional one, that in the horse is especially exhibited the great feature in animal mechanism-the most perfect leverage power. The great effect of raising the

weight over the fulcrum is brought about by the reacting bones, and the flexor muscles of the foot only take up and continue the movement when the weight has passed over the foot, which, under great speed, are functions so rapidly executed as to evade the powers of the eye to discriminate; whilst the same effect, when observed on a heavy Clydesdale horse drawing a waggon, with two tons' weight, ample opportunity is afforded to see every act, and to see one fore foot suspended and flexed, while the other, with its diagonal hind, is pressing on the ground; and the diagonal hind to the fore lifted, is elevated and constringed in a propelling attitude, and the whole weight is bearing on the plantar arches of the pedal bone and the sole of the sustaining feet. The resistance overcome, the body moves, and then, and not till then, the lifted fore foot is extended, and implanted at a distance represented by the degree of velocity attained in the effort.

I hold it as a law, that the same phenomena observed in the slower paces are in operation in the swiftest; and that the quadruped has never less than two feet on the ground in his fleetest, any more than in his slower paces, and that man, and all bipeds, has always one foot in contact with the ground, in progression.

To all those who assert that in fast trotting and galloping the horse flies or moves by a succession of leaps through the air, without for the instant touching the ground, I unhesitatingly say that the notion is opposed to proof, and is inconsistent with all natural laws, whether relating to gravitation or to physiology. I have maintained, as a well-observed fact, that the horse and other quadrupeds do not move, as is almost, if not universally believed, by bounds through the air.

Leaping is a thoroughly distinct function from ordinary progression. So great is the atmospheric pressure on the animal, or, to use another expression, the attraction to the ground, that it is only at great cost of muscular energy that the horse can, for a special object, bound over heights or over open spaces. There is, moreover, the requirement of great powers being exerted in the act of alighting from leaps, all rendering these efforts expensive to the system, and exhaustive; hence rarely called into action.

Those animals which, for given purposes, Nature has endowed with jumping powers, cannot run; and in these we see provision for easing the body down after it has been committed to the air. Thus the grasshopper spreads his slender wings, and the frog his wide-webbed feet. I have extended my observations enough to prove that the quadrupeds and bipeds which run speedily do not mix leaping or fying in the action; and I hold the remark to apply to birds which run or fly; still these are made distinct and unmistakeable. The ostrich runs, and so does the common turkey, or the partridge, until these latter spring from the ground and take wing.

After referring to writers on the horse, on the subject of progression, and finding myself at variance in opinion with them, I had recourse to the works of human and comparative anatomists, and

selected those of G. M. Humphrey, Esq., M.D., F.R.S., of Cambridge, who, in his work on the human foot and the human hand, published in 1861, says, at page 64, "In running the process is much the same as in walking. The chief difference is that, whereas in walking both feet are never off the ground at the same time, and both are upon the ground at the beginning and end of each step, in running, both feet are never on the ground at the same time, and both are off the ground, and the body is flying unsupported through the air, at the beginning and end of each step.'

At page 66, on the action of the horse, the author says, "The distinction between the paces of other animals resembles that between walking and the running of man, and is equally definite. Take, for instance, the walking, trotting, and galloping of the horse. In walking the fore and the hind limbs of the same side are moved together, or nearly together, but they do not leave the ground till the limbs of the opposite side are placed upon it; so that at one period all four limbs are placed upon the ground together.

"In galloping and cantering the horse springs or bounds with all his four limbs at the same time; all the feet are thrown up nearly together; and all reach the ground nearly at the same time ready for another spring.

"I say that the feet are all thrown up nearly or quite together, because the fore and the hind limbs of one side take precedence a little of the others, or lead, as it is called.""

I shall make no remarks on the above, only to say, that I perceive nothing correctly described, though it is a fair representation of what most works on the subject contain, and of the prevailing notions.

The author says, in his large work on the human skeleton, published in 1858, at page, 588, "If greater rapidity be required, running is substituted for walking. The difference is, that the trunk, instead of being quietly delivered over from one leg to the other which is already on the ground to receive it, is thrown forward, with a spring, by the muscles of the leg which is leaving the ground, and remains for a time suspended in the air, or rather flying through the air."

In 1861, whilst on a visit to Birmingham, my mind being engaged in inquiries relative to the progression of the horse and other animals, I went to see some foot-races between "athletes," and shall now extract from my note-book a memorandum which I made at the time:

"I went to Aston Cross; saw three foot-races. Two of these were run at the distance of 110, and the third at 100 yards. I observed every movement of the runners, and fully assured myself, that at no time during the race were both feet of the men disengaged from the ground."

There is no doubt in my mind that the same law of progression

that I had observed in the horse, dog, and other animals, prevails in

man.

At no time in the running, either in starting or in the finishing of the race, was there the slighest deviation or approach to a leap from the ground.

Many false starts, long delays at the post, and attempts to get off, added much to the opportunity for scientific observation.

Much more could be said on many observations made at various times; but I will now adduce one, which I hope may be interesting to others, as the facts revealed were to myself, when I began to observe the same phenomena on animals.

On 16th March, 1863, I went to the Portobello Sands. The tide was high at the time, and I waited until it subsided, when it left a clear beach. Several paces were walked, and a clean imprint of the foot being left on the wet sand, the length of several steps were separately measured, when forty inches was found to be the average distance between the imprint of one foot and that of the other, the measure being carried from the same place in the one to that of the other, viz., the point of the heel-two steps, or double the distance, forming one stride, being also measured, gave eighty inches.

Another trial was then made by running, and in that a distance sufficient to allow full speed to be acquired was ran, and the steps and strides then measured, as in the preceding trial, when sixtythree inches were found to be the length of the step, and 126 inches the distance passed over by each separate foot from its being lifted until it alighted.

Thus, the full action or stride in the walk gave 6 feet 10 inches, and that of the run 10 feet 6 inches.

Nor do the above figures represent the powers and agility of a Deerfoot or a Mills, but are those of a man sixty-two years of age. Either of the two runners above-named would give a significant addition to the distance attained on the occasion referred to.

I will now return to make some further observations on the progression of the horse.

Supposing that we are making observations on the horses running for the Derby, over Epsom Downs, and that the course be so clear that all can be seen as well as I could study and note the horses on Musselburgh race-course, as they ran round me whilst I was quietly placed on a sand-bank, when I saw Oldminster and Caller-Ou doing their best, stride for stride, in their two races in 1861. And if the Derby horses could be observed equally well, and the eye were educated so that their movements could be followed, it would be found that every horse was implanting one foot at a time on the ground-not four, nor two, but one in succession, and at almost equal distance from one another, the extent or length of stride corresponding to the speed kept up at different parts of the course.

Assuming the 'Derby course to be one mile and a-half in length,