HEREDITARY DISEASES OF HORSES AND CATTLE. 281 
more difficult to understand than a character or peculiarity 
conveyed by descent to any part of the solids of the body?* 
Such is Dr. Holland’s opinion : “ The blood/’ he says, “ has 
vitality in every sense in which we can assign it to the solids, 
* Of the instances given of the blood concerned in transmitting here- 
ditary taint, it will be remarked that they are perfectly in accordance with 
the transmission of hereditary likeness, occasionally observed in breeding, 
and which is also even more difficult to conceive or imagine. We allude to 
the curious statement lately brought forward by Mr. James M'Gillavry, of 
Huntly, V.S. — that when a pure animal of any breed has been pregnant to an 
animal of a different breed , such pregnant animal is a cross ever after , the 
purity of her blood being contaminated in consequence of her connection with 
the foreign animal. The two following cases may serve as examples : l 
“ A pure Aberdeenshire heifer was served with a pure Teeswater bull, by 
which she had a first cross calf The following season the same cow was 
served with a pure Aberdeenshire bull; the produce was a crossed calf 
which, when two years old, had short horns, the parents being both polled .” 
Again, “a pure Aberdeenshire cow was served, in 1845, with a cross 
bull, — that is to say, an animal produced between a first-cross cow and a 
pure Teeswater bull. To this bull she had a cross calf. Next season she 
was served with a pure Aberdeenshire bull : the produce was quite a cross 
in shape and colour.” 
The following striking example occurred in Cornwall: — A half-bred mare, 
the property of Mr. Blarney, Caragloose, in the parish of Yeryan, strayed 
from the field, and was served by a donkey : the produce was a mule. The 
following year the mare was taken more care of, and was served by a half- 
bred horse, yet the progeny bore a strong likeness to the previous mule, in 
the reproduction of the upright mane, marks, and even colour and form. 
Is this not a striking lesson to breeders who are in the habit of putting 
their heifers the first time to any mongrel bull, not being aware that the 
purity of her second stock would be contaminated by the first connection ? 
The explanation offered by Mr. M £ Gillavry, of the phenomenon, is inge- 
nious, and consistent with acknowledged facts in physiology. 
££ By the formation of the after-birth [placenta) a connection is established 
between the mother and the living creature ( foetus ) in her womb, through 
which the latter is continually drawing supplies from the mother’s blood, for 
its growth and maintenance. But there are good grounds for believing 
that, through the same channel, the mother is as constantly (though, doubt- 
less, in much less quantity) abstracting materials from the blood of the 
foetus. Now, is it at all unreasonable to suppose that the materials in 
question may be charged with (or have inherent in them) the constitutional 
qualities of the foetus, and that, passing into the body of the mother, and 
mixing there with the general mass of her blood, they may impart those 
qualities to her system.” 
££ The qualities referred to must in part be derived by the foetus from its 
male parent, and be to that extent identical with his. The distinctive pecu- 
liarities, therefore, of that parent may thus come to be engrafted on the 
mother, or to attach in some way to her system ; and if so, what more 
likely than that they should be communicated by her to any offspring she 
may afterwards have by other males ? 
1 For further example read Dr. Harvey’s pamphlet on “Cross Breeding.” 
(Blackwood and Sons, Edinburgh and London.) 
xxviii. 36 
