Francis E. Lloyd 



— 162 — Carnivorous Plants 



on the digestive effect of the secretion on casein, which harmonizes 

 with Dernby's view that a trypsin is present (in Pinguicula). 



The general conclusion may be drawn from the foregoing summaries 

 of work done on digestion in Drosera that this plant does indeed 

 secrete a ferment which can act upon proteins and reduce them to 

 substances which can be and are absorbed for nutriment. If food 

 materials in the form of an abundance of insects, pollen, etc. (Darwin) 

 are present so that the antiseptic effect is incomplete, bacteria may 

 (particularly according to Okahara) assist in rendering such foods 



available to the plant. 



The abundance of fats in the bodies of insects would suggest 

 the presence of a lipase in Drosera, but such has not been found. 

 Whether lecithin and fatty acids might be absorbed by infiltration 

 (as lecithin is taken in by the human intestine according to Shocot- 

 YOFF, fide ScHMiD, 1912) is a matter of speculation, though Goebel 

 thought that he found fats to be absorbed by the glands of Pingui- 

 cula and Utricularia. 



Significance of carnivory for the plant. ~ Although. Darwin left 

 no room for doubt that Drosera is able to catch, digest and absorb 

 the products of digestion, it remained a question if this abihty is 

 of advantage to the plant in furthering its growth and development. 

 It was natural that Francis Darwin (1878) should take up the cud- 

 gels in his father's behalf. He grew plants, obtained from the field, 

 in shallow dishes duly protected so as to prevent insects from reaching 

 them. These he divided into two lots, one of which he fed, the other 

 remaining unfed. The result showed the indubitable conclusion that 

 the plants which were fed were more vigorous, produced more and 

 stronger inflorescences and seed than the unfed. Similar results were 

 obtained by Kellermann and v. Raumer (1878). Busgen (1883) 

 then pointed out that plants grown from winter buds show a wide 

 range of development to begin with, so that an experiment with these 

 is really a handicap race. To avoid this he used plants grown from 

 seed, so that his plants started out from scratch. The results were 

 even more striking than those of the previous workers. In the table 

 herewith the results of the three authors are compared in terms of 

 percentage, the quantities for the unfed plants being 100: — 



Fr. Darwin Kellermann & Busgen 



1878 V. Raumer, 1878 1883 



Number of inflorescences 164.9 



Number of capsules i94-4 



Total weight of seed 379-7 



100 152: 100 300: 100 



100 174: 100 533: 100 



100 capsules 205: 100 



And in terms of dry weight: Solution Spring 



nutrient water 



Winter buds, i Feb 173: 100 



Winter buds, 3 Apr 213: 100 



Entire plant, end of 2nd. year 296: 100 174: 100 



Inflorescences 141. i : 100 



Plants minus Inflorescences 12 1.5: 100 



{flde Busgen) 



While these figures speak for themselves, I venture to quote briefly 

 from these authors. Kellermann and von Raumer: "The general 



