Chap. V. EFFECTS OF OEGANIC FLUIDS. 83 



exist wMcli are not coagulated by boiling water, but are con- 

 verted into soluble peptones. 



On three occasions chopped cabbage-leaves* were boiled in 

 distilled water for 1 hr. or for 1^- hr. ; and by decanting the 

 decoction after it had been allowed to rest, a pale dirty green 

 fluid was obtained. The usual-sized drops were placed on 

 thirteen leaves. Their tentacles and blades were inflected after 

 4 hrs. to a quite extraordinary degree. Next day the protoplasm 

 within the cells of the tentacles was found aggregated in the 

 most strongly marked manner. I also touched the viscid secre- 

 tion round the glands of several tentacles with min,ute drops of 

 the decoction on the head of a small pin, and they became well 

 inflected in a few minutes. The fluid proving so powerful, one 

 part was diluted with three of water, and di'ops were placed on 

 the discs of five leaves ; and these next morning were so much 

 acted on that their blades were completely doubled over. We 

 thus see that a decoction of cabbage-leaves is nearly or quite as 

 potent as an infusion of raw meat. 



About the same quantity of chopped cabbage-leaves and of 

 distilled water, as in the last experiment, were kept in a vessel 

 for 20 hrs. in a hot closet, but not heated to near the boiling- 

 point. Drops of this infusion were placed on four leaves. One 

 of these, after 23 hrs., was much inflected ; a second slightly ; a 

 third had only the submarginal tentacles inflected; and the 

 fourth was not at all affected. The power of this infusion is 

 therefore very much less than that of the decoction ; and it is 

 clear that the immersion of cabbage-leaves for an hour in water 

 at the boihng temperature is much more efficient in extracting 

 matter which excites Drosera than immersion during many 

 hours in warm water. Perhaps the contents of the cells are 

 protected (as Schiff remarks with respect to legumin) by the 

 walls being formed of cellulose, and that until these are rup- 

 tured by boiling-water, but little of the contained albuminous 

 matter is dissolved. We know from the strong odour of cooked 

 cabbage-leaves that boiling water produces some chemical 

 change in them, and that they are thus rendered far more 

 digestible and nutritious to man. It is therefore an interesting 



* The leaves of young plants, and the outer leaves of mature 



before the heart is formed, such plants 1 • 6 per cent. Watts' ' Diet, 



as were used by me, contain 2-1 of Chemistry,' vol. i. p. 653. 

 per cent of albuminous matter, 



