remark that the flexible horn is the best modifier of concussion, and that as the thickness of metal increases, so does the jar.
But this supposed jar is the least of the ills attending the use of heavy shoes. The difference in the muscular fatigue of a limb, after carrying at its extremity for a long distance a clumsy mass of iron, weighing, perhaps, two pounds, and afterwards another of one or one and a half pounds, is astonishing. I cannot, perhaps, do better than quote the remarks of Professor Bouley, when discussing this subject in Paris a short time ago. He says, speaking of the omnibus horses: 'If, at the termination of a day's work, we calculate the weight represented by the mass of heavy shoes that a horse is condemned to carry at each step, we will arrive at a formidable array of figures, and in this way be able to estimate the amount of force uselessly expended by the animal, in raising the shoes that surcharge his feet. The calculation I have made possesses an eloquence that dispenses with very long commentaries. Suppose that the weight of a shoe is 1000 grammes; it is not excessive to admit that a horse trots at the rate of one step every second, or sixty steps a minute. In a minute, then, the limb of a horse whose foot carries 1 kilogramme makes an effort necessary to raise, kilogramme after kilogramme, a weight of 60 kilogrammes. For the four limbs, this weight in a minute is represented by 60 X 4 = 240 kilogrammes; for the four feet during an hour the weight is 14,000 kilogrammes; and for four hours, the mean duration of a day's work in these omnibuses, the total amount of weight raised has reached the respectable figure of 57,000 kilogrammes. But the move-
