Mr.Hindmarsh had contributed a paper "On the Wild Cattle of Chillingham Park" to the "Annals and Mag.Nat.

Hist." Volume II., page 274, 1839.) Down, May 12th [1861].
I thank you sincerely for your prompt and great kindness, and return the letter, which I have been very glad to see and have had copied.
The increase is more rapid than I anticipated, but it seems rather conjectural; I had hoped that in so interesting a case some exact record had been kept.

The number of births, or of calves reared till they followed their mothers, would perhaps have been the best datum.

From Mr.Hardy's letter I infer that ten must be annually born to make up the deaths from various causes.

In Paraguay, Azara states that in a herd of 4,000, from 1,000 to 1,300 are reared; but then, though they do not kill calves, but castrate the young bulls, no doubt the oxen would be killed earlier than the cows, so that the herd would contain probably more of the female sex than the herd at Chillingham.