ote.); and this
leads me to ask how much faith may I put in the statement that male
birds will sing in rivalry until they injure themselves. Yarrell
formerly told me that they would sometimes even sing themselves to
death. I am sorry to hear that the painted bullfinch turns out to be a
female; though she has done us a good turn in exhibiting her jealousy,
of which I had no idea.

Thank you for telling me about the wildness of the hybrid canaries:
nothing has hardly ever surprised me more than the many cases of
reversion from crossing. Do you not think it a very curious subject? I
have not heard from Mr. Bartlett about the Gallinaceae, and I daresay I
never shall. He told me about the Tragopan, and he is positive that the
blue wattle becomes gorged with blood, and not air.

Returning to the first of the last three letters. It is most curious the
number of persons of the name of Jenner who have had a strong taste for
Natural History. It is a pity you cannot trace your connection with the
great Jenner, for a duke might be proud of his blood.

I heard lately from Professor Rolleston of the inherited effects of an
injury in the same eye. Is the scar on your son's leg on the same side
and on exactly the same spot where you were wounded? And did the wound
suppurate, or heal by the first intention? I cannot persuade myself
of the truth of the common belief of the influence of the mother's
imagination on the child. A point just occurs to me (though it does
not at present concern me) about birds' nests. Have you read Wallace's
recent articles? (441/2. A full discussion of Mr. Wallace's views is
given in "Descent of Man," Edition I., Volume II., Chapter XV. Briefly,
Mr. Wallace's point is that the dull colour of the female bird is
protective by rendering her inconspicuous during incubation. Thus the
relatively bright colour of the male would not simply depend on sexual
selection, but also on the hen being "saved, through Natural Selection,
from acquiring the conspicuous colours of the male" (loc. cit., page
155).) I always distrust myself when I differ from him; but I cannot
admit that birds learn to make their nests from having seen them
whilst young. I must think it as true an instinct as that which leads a
caterpillar to suspend its cocoon in a particular manner. Have you had
any experience of birds hatched under a foster-mother making their nests
in the proper manner? I cannot thank you enough for all your kindness.

LET