PANSION 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 t