To W. R. Grove   9 July [1871]¹

Dear Grove

I am much obliged for your interesting letter. I doubt whether your theory will hold: look at the the upper parts of the palm of the hand.— I believe that the sudorific pores run along the little ridges; but what bearing this may have, I know not, on their course.—²

I believe I had heard, but had utterly forgotten, about the secretion of milk from the glands of Boys at puberty: my wife doubts whether this holds good with girls, & if so the fact is very perplexing.³

I have given evidence of protection from the mane in the Lion & about Horses; but from enquiries made I doubt whether the beard protects the throats of monkeys & a fortiori not of goats.⁴

I am particularly glad to hear your case of the setter; for I have seen exactly the same fact, including backing (which seems the most marvellous point) in a puppy pointer when first taken out.—

The wildest birds learn with surprising quickness that a Rail-way Train at full speed is not dangerous.—

Yours sincerely & obliged | Ch Darwin