76 " DROSEKA ROTUNDIFOLIA. Cilvp. V. 



CHAPTEK V. 



The Effects of Non-nitrogenous and Nitrogenous Organic Fluids 

 ON THE Leaves. 



Non-nitrogenous fluids — Solutions of gum arabic — Sugar — Starch 

 — Diluted alcohol — Olive oil — Infusion and decoction of tea — 

 Nitrogenous fluids — Milk — Urine — Liquid albumen — Infusion 

 of raw meat — Impure muciis — Saliva — Solution of isinglass — 

 Difference in the action of these two sets of fluids — Decoction of 

 green peas — Decoction and infusion of cabbage — Decoction of 

 grass leaves. 



AYhen, in 1860, 1 first observed Drosera, and was led to 

 believe that the leaves absorbed nutritious matter from 

 the insects which they captured, it seemed to me a 

 good plan to make some preliminary trials with a few 

 common fluids, containing and not containing nitro- 

 genous matter ; and the results are worth giving. 



In all the following cases a drop was allowed to fall 

 from the same pointed instrument on the centre of the 

 leaf; and by repeated trials one of these drops was 

 ascertained to be on an average very nearly half a 

 minim, or ^^ of a fluid ounce, or '0295 ml. But these 

 measurements obviously do not pretend to any strict 

 accuracy ; moreover, the drops of the viscid fluids were 

 plainly larger than those of water. Only one leaf on 

 the same plant was tried, and the plants were col- 

 lected from two distant localities. The experiments 

 were made during August and September. In judging 

 of the effects, one caution is necessary : if a drop of 

 any adhesive fluid is placed on an old or feeble leaf, 

 the glands of which have ceased to secrete copiously, 

 the drop sometimes dries up, especially if the plant 



