From Michael Foster   [26 June 1871]¹

My dear Sir

I have written to my man at Cambridge to send you by post a bottle of urari of which please use as much as you want—& when you have quite done with it I will have the remainder back.² I have two stocks—one Sharpey³ gave me—gathered by D^r. Dalton,⁴—the other purchased in Leipzig— I don’t know which will reach you because I don’t quite know which my man will lay his hands upon.

As to doze I hardly know what to say— Urari does not neutralize strychnia but prevents the muscular manifestations of the action of strychnia— Hence any dose sufficient to paralyse completely the motor nerves (and for a frog I generally take a drop of two of a solution made by mixing thus much 0 in about ȝj⁵ of water) will negative the action of almost any qty of strychnia great or small. The urari is eliminated slowly so that by the time the action of even a small dose of urari is passing off, the effect of a large dose of strychnia has also passed away.⁶

I think I am right in saying that in the absence of histologically distinct nervous elements urari seems inert— ex gr.⁷ amoebae go their ways as usual in even strong solutions of it—& protoplasm generally seems to be unaffected by it— I believe these are Kühne’s results.⁸

It is extremely soluble in cold water—& the clear filtrate possesses all the virtues.

Believe me | Yours ever truly | M. Foster