My dear Sir

I write a single line to acknowledge the receipt of your kind letter.² I will not attempt to answer it by this post for it so happens that my time has been so occupied since I received it that I could do so properly.

I may however just mention that D^r Osler has made some comparative observations on the behaviour of colourless blood corpuscles in solutions of sodium and potassium salts of the same strength. He finds that in the latter the amœboid movements continue nearly as long as in the former.³

I am, my dear Sir | very faithfully yours | J S B Sanderson