THE PHYSIOLOGY OF PITCHER-PLANTS. 



103 



false digestion observed by M. Hooker were, without doubt, due 

 to the activity of micro-organisms introduced from without 

 rather than to the secretion of the plant." Another writer in 

 the same strain is Tischutkin (" Ber. d. deutsch. bot. Ges.," 1889 ; 

 " Bot. Centralblatt," 50, 1892), who asserts that the solution of 

 proteids in the liquid of insectivorous plants (incl. Nepenthes) is 

 due to the activity of micro-organisms which are introduced, 

 like the insects, from outside, and that these plants do not digest 

 the insects, but only absorb the products of their putrefaction. 



Had these two writers made themselves acquainted with all 

 the previously ascertained facts, they would not, I venture to 

 think, have thought it worth while to express these views. In 

 order to fully reassure myself on the subject, I have made, 

 during the last two years, a number of experiments with 

 Nepenthes (chiefly N. Mastersiana), with special reference to the 

 statements of Dubois and Tischutkin. I propose to publish a 

 detailed paper on the subject before long, so I will now content 

 myself with a brief summary of the chief results which I have 

 obtained* : — 



(1) I have confirmed my previous observation that a glycerin 

 extract of the pitchers can be prepared (after thorough washing, 

 and lying for 24 hours in absolute alcohol), which readily digests 

 blood-fibrin, at a temperature of 35°-40° C, in presence of 

 dilute HC1. 



(2) I have repeatedly found that the liquid taken from an 

 unopened pitcher digests blood-fibrin, under the above conditions, 

 with great rapidity (1-2 hours). 



(3) Liquid from open pitchers digests blood-fibrin very 

 rapidly under the above conditions, the digestive action being 

 much more rapid than any putrefactive change attributable to 

 micro-organisms ; further, the digestion goes on, though less 

 rapidly, in the presence of antiseptics [e.g. thymol, chloroform, 

 potassium cyanide). 



(4) The liquid obtained from the pitchers, if filtered, may 

 be kept in a bottle for a considerable time (months) without 

 undergoing putrefaction, and it still retains its digestive power. 



These results will, I trust, suffice to prove that the pitcher 



* I am very much indebted to Messrs. Veitch for supplies of liquid 

 from the pitchers, as also for valuable specimens of Nepenthes and other 

 pitcher- plants. 



