To William Waring   12 January [1874]¹

My dear Sir

I thank you for your extremely kind letter.— One point, which you incidentally mention is very interesting & new to me, viz that when many puppies are born, a few are generally small & weakly.—² As you kindly permit me to trouble you again, I sh^d. like to put the same case as before in a rather different way.— If a man kept a rather large lot of fairly good greyhounds, say 20 or 30, would not these increase at so quick a rate that he would be obliged to destroy some, & would it be sufficient to destroy merely any small & weakly puppies in the larger littlers? If so, would he destroy more male or female puppies; & this, I suppose would depend on whether males or females are the most valuable for coursing.—

Would it be possible for you (if not causing too much trouble) to ask some large breeder of greyhounds whether he rears all his puppies; & if does not rear all, whether he destroys more males or females?

I feel so much interest with respect to greyhounds, because a few years ago I had all the returns made for several years to the Field newspaper tabulated, & I know exactly the proportion of male to female births viz 110 males to 100 females.—³

I thank you cordially for your kindness & remain, my dear Sir | Yours sincerely | Ch. Darwin