304 THE PRINCIPLES QF Part II. 



periods each of four years : this, however, may be 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 ' Field ' 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 HO'l 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. Moieover, I find that seveial 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 



