70 DROSERA ROTUNDIPOLIA. [Chap. V. 



fected. The power of this infusion is therefore very much less than 

 that of the det-oc-tion ; and it is clear that the immersion of cabbage 

 leaves for an hour in water at the boiling temperature is much more 

 etiicient in extracting matter which excites Drosera than immersion 

 during many hours in wai-m 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 ruptured 

 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 fact that water at this temperature ex- 

 tracts matter from them which excites Drosera to an extraor- 

 dinary degree. 



Grasses contain far less nitrogenous matter than do peas or cab- 

 bages. The leaves and stalks of three common kinds were chopped 

 and boiled for some time in distilled water. Drops of this decoction 

 (after having stood for 24 hrs.) were placed on six leaves, and acted 

 in a rather i)eculiar manner, of which other instances will be given 

 in the seventh chapter on the salts of ammonia. After 2 hrs. 30 m. 

 four of the leaves had their blades greatly inflected, but not their 

 exterior tentacle; and so it was with all six leaves after 24 hrs. 

 Two days afterwards the blades, as well as the few submarginal ten- 

 tacles which had been inflected, all re-expanded; and much of the 

 fluid on their discs was by this time absorbed. It appears that the 

 decoction strongly excites the glands on the disc, causing the blade 

 to be quickly and greatly inflected; but that the stimulus, differ- 

 ently from what occurs in ordinary cases, does not spread, or only in 

 a feeble degree, to the exterior tentacles. 



1 may here add that one part of the extract of belladonna (pro- 

 cured from a druggist) was dissolved in 437 of water, and drops were 

 placed on six leaves. Next day all six were somewhat inflected, and 

 after 48 hrs. were completely re-expanded. It was not the included 

 atropine which produced this effect, for I subsequently ascertained 

 that it is quite powerless. I also procured some extract of hyoscya- 

 mus from three shops, and made infusions of the same strength as 

 before. Of these three infusions, only one acted on some of the 

 leaves, which were tried. Though druggists believe that all the 

 albumen is precipitated in the preparation of these drugs, I can- 

 not doubt that some is occasionally retained ; and a trace would be 

 sufncient to excite the more sensitive leaves of Drosera. 



