hereditary, and has been traced through five generations,
in which it was confined to the female sex.

With respect to the colour of the iris: deficiency of colouring matter
is well known to be hereditary in albinoes. The iris of one eye being
of a different colour from that of the other, and the iris being
spotted, are cases which have been inherited. Mr. Sedgwick gives, in
addition, on the {10} authority of Dr. Osborne,[19] the following
curious instance of strong inheritance: a family of sixteen sons and
five daughters all had eyes "resembling in miniature the markings on
the back of a tortoiseshell cat." The mother of this large family had
three sisters and a brother all similarly marked, and they derived this
peculiarity from their mother, who belonged to a family notorious for
transmitting it to their posterity.

Finally, Dr. Lucas emphatically remarks that there is not one single
faculty of the eye which is not subject to anomalies; and not one which
is not subjected to the principle of inheritance. Mr. Bowman agrees
with the general truth of this proposition; which of course does not
imply that all malformations are necessarily inherited; this would not
even follow if both parents were affected by an anomaly which in most
cases was transmissible.

Even if no single fact had been known with respect to the inheritance of
disease and malformations by man, the evidence would have been ample in the
case of the horse. And this might have been expected, as horses breed much
quicker than man, are matched with care, and are highly valued. I have
consulted many works, and the unanimity of the belief by veterinaries of
all nations in the transmission of various morbid tendencies is surprising.
Authors, who have had wide experience, give in detail many singular cases,
and assert that contracted feet, with the numerous contingent evils, of
ring-bones, curbs, splints, spavin, founder and weakness of the front legs,
roaring or broken and thick wind, melanosis, specific ophthalmia, and
blindness (the great French veterinary Hazard going so far as to say that a
blind race could soon be formed), crib-biting, jibbing, and ill-temper, are
all plainly hereditary. Youatt sums up by saying "there is scarcely a
malady to which the horse is subject which is not hereditary;" and M.
Bernard adds that the doctrine "that there is scarcely a disease which does
not r