Dear Sir

To M^r Alessandro Garbi of Florence, who interests himself very much for the progress of natural science and especially for what you may allow to call Darwinism, I am indebted for the occasion he offers me, to send you this letter.

In first line many thanks for having sent me your most interesting researches on carnivorous plants.¹

As in your book you insist repeatedly on the analogy of the interesting facts you have found concerning the laws of production of the digesting juice in Drosera with what I had found for the gastric juice of the dog, and had called saturation of the stomac by foregoing absorption, it would please you to hear that, notwithstanding the strong opposition my doctrine has found among many physiologists, I am after a carefull repitition of all the experiments fully satisfied that the facts induced by me are true and exact.²

But repeating the experiments under various circumstances and in varied conditions, seaking the source of the contradictions, I found that in one point I must modify my former opinion

I spoke in my lessons of a production of pepsine by absorbed matters.³ This is not quite exact. As I have indicated in the Journal la Nazione several years ago (and this has been confirmed by some researches made in the Laboratory of Heidenhain at Breslau) a substance which I shall call propepsine is constantly present and produced in the stomac, even after the digestion of a very copious meal, but this propesine without beeing modified has no digesting power and acquires it in the living body only by absorption of peptogeneous substances⁴

But the same modification of the propepsine can be obtained by decomposition produced by a maceration or infusion too much prolongated, or in water, or in some strong acids or in certain salts.— But other salts added in a due proportion to distilled water can hinder the decomposition and extract only the preformed pepsine.

The progress of this decomposition was the cause of some opinions differing from the results of our researches   In general it has been attributed to the stomac too high a digestive power, and some authors misled by theyr method of infusion, have gone so far as to deny that infusion may ever extract whole the pepsine contained in a stomac, even when it were continued for a very long period. Even those who deny the facts of saturation by absorption pretending that the quantity of pepsine never could be exhausted during the life, found theyr opinion on experiments in which they have artificially produced pepsine by maceration.

The best method for preventing all decomposition is the study of digestion in the living stomac by means of the fistula.⁵ This method, with the precautions I have indicated leads us unvariably to the same results and offers the great advantage of permitting the repetition of the same experiment in the same animal under various conditions.

I have begun some researches on the existence of a propepsine in Drosera, by extracting the leaf with glycerine. My experiments were but few and till now without result.

Another series of facts which has highly interested me is the indication of a sort of reflex action in the Drosera (pg 242 & 276 of your work.)⁶

As you justly observe we cannot be to cautious in judging this phenomen, which I wished to study in the living plant, by the method we use in animal physiologie⁷

I dont know wether I can procure me in Geneva the Drosera in a good state. During this last year in Florence my activity has been paralysed by the strong persecutions against the experimental physiology. Next July or towards the end of June I shall leave Florence for occupying the chair of physiology on the newly created school of medecine at Geneva⁸

I take leave to send to you and to your son D^r. G Darwin (whom they may especially interest) some of my last publications and an elder one by which you may judge how interesting it must be for me, to have a true and undoubtful prove of the existence of reflex action in a plant or rather in what till now we have called plants.⁹

Excuse the imperfect form of this letter. It is the first I venture to write in your language. | Believe me | Dear Sir | Yours truely | Maurizio¹⁰ Schiff

Florence 8/5 76

To D^r Charles Darwin

I hope you have received last year my essay on the method of experiments in living animals, which I sent you by D^r Fraser of Edinburgh¹¹ | Schiff