18 
Hereditary Diseases of Sheep and Pigs. 
and feet, or even black spots on the same parts of the body. 
Grey legs and faces are the hereditary markings of many families 
of pure Leicester sheep. ^Elian, a Latin author of the date 
B.C. 320, mentions tliat the sheep on the banks of the river 
Xanthus were remarkable for their yellow fleeces ;* and Dr. 
Buchanan, while journeying through Mysore, remarked that in 
that country there were red, black, and white sheep ;f and in all 
these cases the particular colour of the parents reappeared in 
the offspring, so long as the different families remained unmixed. 
The existence or non-existence of horns, their length and con- 
figuration when present, the quantity and quality of the wool, 
and many other peculiarities of different families and varieties 
of sheep, are all decidedly hereditary. Besides these physical 
qualities there can be no doubt of the dispositions and habits 
of sheep being also hereditary, although in this respect we have 
not the same opportunities of judging as in horses or dogs. 
Among pigs may also be discovered numerous illustrations of 
the law of hereditary transmission quite as striking as among 
sheep. Length of limb, form of carcase, size and form of head, 
erect or pendulous ear, early maturity, and fattening capabilities, 
are all reproduced in the offspring. Many families are remark- 
able during many generations for peculiar colours and markings. 
Throughout most parts of America the wild hogs are quite 
black, but at Melgara and some other places they have a white 
band running along the belly and extending over the back; 
while in some of the warmer parts of the New World they are 
red.J Blumenbach mentions that the swine of Piedmont are 
black, those of Normandy white, those of Bavaria reddish brown, 
and also that all those seen by him at a large fair at Salenche 
•were black. In our own country too these peculiar colours and 
markings often continue through many generations the hereditary 
insignia of certain families of swine. In many parts of Asia, 
and wherever the climate is fine and mild, the skin is delicate 
and almost bare, or only thinly covered with a few soft hairs ; 
but in cold, exposed, and mountainous regions it is plentifully 
covered with thick fur, beneath which is often found a sort of 
wool. These differences, though originally depending on the 
modifying influence of external circumstances, have become per- 
manent and hereditary, and continue to be produced for several 
generations, even when the animals are placed under entirely 
different circumstances. In Hungary, Sweden, and some parts 
of England, swine are found with solid hoofs ; in the island of 
* Researches into the Physical History of Mankind, by James Prichard, M.D. 
1826. Vol. I., p. 194. 
t Op. cit., p. 195. 
J Natural History of Man, by James Prichard, M.D., p. 29. 
