My dear D^r. Playfair

I must write one line to thank you for your very kind letter, & to say that after despatching my last note, it suddenly occurred to me that I had been rude in calling one of the provisions of your Bill, “monstrous” or “absurd”—I forget which—.² But when I wrote the expression it was addressed to the bigots, who I believed had forced you to a compromise.

I cannot understand what D^r. B. Sanderson could have been about not to have objected with respect to clause of not demonstrating on animals rendered insensible.—³ I am extremely sorry that you have had trouble & vexation on the subject.— It is a most disagreeable & difficult one.— I am not personally concerned, as I never tried an experiment on a living animal, nor am I a physiologist, but I know enough to see how ruinous it w^d be to stop all progress in so grand a science as physiology.

I commenced the agitation amongst the physiologists for this reason, & because I have long felt very keenly on the question of useless vivisection, & believed though without any good evidences that there was not always, even in this country, care enough taken.—

Pray forgive this note, so much about myself. & believe me | Yours sincerely | Ch Darwin