304 
THE PRINCIPLES OF 
Part IT. 
periods each of four years : this, however, may he accidental ; at 
least I can detect nothing of the kind with man in the decennial 
table in the Registrar’s Report for 1866. I may add that certain 
mares, and this holds good with certain cows and with women, 
tend to produce more of one sex than of the other ; Mr. Wright of 
Yeldersley House, informs me that one of his Arab mares, though 
put seven times to different horses, produced seven fillies. 
Dogs . — During a period of twelve years, from 1857 to 1868, the 
births of a large number of greyhounds, throughout England, have 
been sent to the 4 Field 5 newspaper ; and I am again indebted to 
Mr. Tegetmeier for carefully tabulating the results. The recorded 
births have been 6878, consisting of 3605 males and 3273 females, 
that is, in the proportion of HOT males to 100 females. The 
greatest fluctuations occurred in 1864, when the proportion was as 
95*3 males, and in 1867, as 116*3 males to 100 females. The above 
average proportion of 110*1 to 100 is probably nearly correct in the 
case of the greyhound, but whether it would hold with other domes- 
ticated breeds is in some degree doubtful. Mr. Cupples has enquired 
from several great breeders of dogs, and finds that all without 
exception believe that females are produced in excess ; he suggests 
that this belief may have arisen from females being less valued and 
the consequent disappointment producing a stronger impression on 
the mind. 
Sheep . — The sexes of sheep are not ascertained by agriculturists 
until several months after birth, at the period when the males are 
castrated ; so that the following returns do not give the proportions 
at birth. Moreover, I find that several great breeders in Scotland, 
who annually raise some thousand sheep, are firmly convinced that 
a larger proportion of males than of females die during the first one 
or two years ; therefore the proportion of males would be somewhat 
greater at birth than at the age of castration. This is a remarkable 
coincidence with what occurs, as we have seen, with mankind, and 
both cases probably depend on some common cause. I have re- 
ceived returns from four gentlemen in England who have bred low- 
land sheep, chiefly Leicesters, during the last ten or sixteen years ; 
they amount altogether to 8965 births, consisting of 4407 males 
and 4558 females ; that is in the proportion of 96*7 males to 100 
females. With respect to Cheviot and black- faced sheep bred in 
Scotland, I have received returns from six breeders, two of them on 
a large scale, chiefly for the years 1867-1869, but some of the 
returns extending back to 1862. The total number recorded 
amounts to 50,685, consisting of 25,071 males and 25,614 females, 
or in the proportion of 97*9 males to 100 females. If we take the 
English and Scotch returns together, the total number amounts 
