Dear Sir

The following is the result of some experiments made by D^r Brunton and myself with the cobra poison, on ciliary action, and also on muscles.— Some ciliated epithelium from the mouth of a frog was placed under the microscope, divided into two portions, one was moistened with water.— The other with a solution of cobra poison of ^.03 gramme Poison to 4^.6. cubic centimetres of water—¹

The motions of ciliae in both were vigorous & those in the poison solution seemed even more vigorous than the other, at first.—

The movements of the ciliae in the poisoned solution soon began to diminish in force— they became languid and ceased altogether in a few minutes—whilst the non-poisoned ciliæ were still acting vigorously. Evidently, the action of the poison was to destroy the power of ciliary motion, having on the first contact perhaps. increased it for a moment. The movements in the poisoned solution lasted, in one experiment, between 15 and 20 minutes. In another experiment they lasted a shorter time—

The following experiment was also made— The Gastrocnemius Muscle of a frog was separated and placed in water   The other gastroc^ns. muscle of same frog was separated and placed in the solution of Cobra poison—already moistened.— The muscle immediately contracted in marked contradistinction to the muscle placed in the non poisoned fluid.— The experiment was made at 1.25 ^P.M. at 1.45—the poisoned muscle had lost its irritability not responding to the strongest current, whilst the non poisoned muscle continued to contract vigorously with a weak current (at 11).² It is obvious therefore, that the action of this poison is to weaken & destroy muscular contractability—³

This experiment must be tried in Amœba.   when it is—you shall know the result.—⁴

I have written to D^r Weir Mitchell to ask him for some more Crotalus poison⁵   I will send you some if he complies with my request.— It differs somewhat in its action from the colubrine poison.⁶

Believe me | Yours very truly | J. Fayrer