My dear Sir,

Ever since I last wrote I have been endeavouring to repeat the experiment with the Guinea Pigs, only one has bred, the same Sow that, was kept out of doors last spring went to the Boar this year on the afternoon of Friday May the second— I placed her in a hutch and kept her by the kitchen fire until the 10^th. of July when I removed her not wishing her to have young before the children, Saturday morning July the 12^th. I found she had kindled being exactly the same time namely a few hours over the ten weeks which she went when exposed to the cold and I hope you will consider this quite conclusive¹   her young two in number were dead   one apparently had been long dead   the other died at the birth.

I think we may set down the period of gestation as ten weeks and that warmth has no influence   I wish to part with the Guinea Pigs   shall I send them to you? there is the Boar and one Sow that Mess^rs. Baker sent,² an old Sow I got here, and a young one bred last year   four in all, and though I have watched them closely I have not seen any desire in the other Sows to breed

I have a Rat’s tooth that forms a complete circle   the rat was blind and very thin   both the upper teeth, had grown in a circle the points growing into the roof of the mouth and almost touching the roots. one was broken by the dog killing the rat   the other is perfect and at your service if you think it worth acceptance,

I have also the skull of my old dog a bull terrier 12 years old, would you like it,? I have not yet seen any notice of your work on Variation under domestication so I conclude it is not yet published³   I trust that your health and also your daughters has improved since I last heard,⁴ I do not call to mind that I have anything else to communicate,

I am sorry to say I am not yet free from my law suit   I hope however for the final settlement in November unless any unforseen hinderance prevents,⁵

With best wishes believe me | My dear Sir | Your’s truly | B P Brent

To C Darwin Esq^re