C. EXPANSION AND CONTRACTION OF THE HOOF.

Among other questions productive of heated argument come those relating to expansion of the horse’s hoof.  In the past many observers have strenuously insisted on the fact that expansion and contraction regularly occur during progression.  Opposed to them have been others equally firm in the belief that neither took place.  Quite within recent times this question also has been settled once and for all by the experiments of A. Lungwitz, of Dresden.  His conclusions were published in an article entitled ’Changes in Form of the Hoof under the Action of the Body-weight.’[A]

[Footnote A:  Journal of Comparative Pathology and Therapeutics, vol. iv., p. 191.  The whole of the matter in this article, from which we have borrowed Figs. 35 and 36, is too long for reproduction here.  It forms, however, most instructive reading, and its careful perusal will well repay everyone interested in this most important question (H.C.R.).]

In connection with this it is interesting to note how, all unconsciously, two separate observers were simultaneously arriving by almost identical means at an equally satisfactory answer to the question.  Prior to the publication of Lungwitz’s article on the subject, Colonel F. Smith, A.V.D., had arrived at similar conclusions by working on the same methods.

[Illustration:  Fig. 35.  I. Electric Bell with Dry Element. a, Under part, with box, for the dry element; 6, roller for winding up the conducting-wires; c, dry element, with screw-clamp for attachment of the conducting-wires; c’, conducting-wire leading to the screw-clamp, with contact-spring in c’, Fig. 2, or to the wall in Fig. 3; d, upper part, with bell; d’, conducting-wire to the shoe d’ in Figs. 2 and 3; e, strap for slinging the apparatus around the body of the assistant or rider; f, connecting-wire between bell and dry element.]

[Illustration:  Fig. 35.  II.  Hoof Shod with Shoe provided with Toe-piece and Calkins; Wall of the Hoof covered with Tinfoil. a, Heel angle, with b, the contact-screws; c, screw-clamp, with contact-spring (isolated from the shoe); c’ conducting-wire from the same; d, screw-clamp, with conducting-wire (d’) screwed into the edge of the shoe; e, nails isolated by cutting a small window in the tinfoil.]

[Illustration:  Fig. 35.  III.  Hoof Shod with Plain Shoe; Horny Wall covered with Tinfoil. a, Toe and heel angle, with b, the contact-screws; c, conducting-wire passing from the tinfoil on the wall; d, conducting-wire passing from the shoe; c’, d’, ends of the conducting-wires, which must be imagined connected with the ends c’, d’, passing from the apparatus.]

It is unnecessary for our purpose here to minutely describe the exact modus operandi of these two experimenters.  Briefly, the method of inquiry adopted in each case was the ‘push and contact principle’ of the ordinary electric bell, and the close attention which was paid to detail will be sufficiently gathered from Figs. 35 and 36.