LETTER 717. TO J. BURDON SANDERSON. September 13th [1873].

How very kind it was of you to telegraph to me. I am quite delighted that you have got a decided result. Is it not a very remarkable fact? It seems so to me, in my ignorance. I wish I could remember more distinctly what I formerly read of Du Bois Raymond's results. My poor memory never serves me for more than a vague guide. I really think you ought to try Drosera. In a weak solution of phosphate of ammonia (viz. 1 gr. to 20 oz. of water) it will contract in about five minutes, and even more quickly in pure warm water; but then water, I suppose, would prevent your trial. I forget, but I think it contracts pretty quickly (i.e. in an hour or two) with a large drop of a rather stronger solution of the phosphate, or with an atom of raw meat on the disc of the leaf.