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Show 216 DROSERA ROTUNDIFOLIA. CHAP. IX. may we not suppose* that the interstices of the walls of tho glands were blocked up with the molecules of these five substances so that they were rendered impermeable to water; for had w~tcr entered, we know from the ten tTials that the phosphate would not afterwaTds have produced any effect? It furtheT appears that the molecules of the carbonate of ammonia can quickly pass into glands which, from having been immersed foT 20 m. in a weak solution of sugar, either absorb the phosphate very slowly or are acted on by it very slowly. On the other hand, glands, however they may have been treated, seem easily to permit the subsequent entrance of the molecules of carbonate of ammonia. Thus leaves which had been immersed in a solution (of one part to 437 of water) of nitrate of potassium for 48 hrs.-of sulphate of potassium for 24 hrs.-and of the chloride of potass~um for 25 hrs.-on being placed in a solution of one part of carbonate of ammonia to 218 of water, had their glands immediately blackened, and after 1 hr. their tentacles somewhat inflected, and the protoplasm aggregated. But it would be an endless task to endeavour to ascertain tbe wonderfully diversified effects of various solutions on Drosera. Alcohol (one part to seven of water).-It has already been shown that half-minims of this strength placed on the discs of leaves do not cause any inflection ; and that when two days afterwards the leaves were given bits of meat, they became stTongly inflected. Four leaves were immersed in this mixture, and two of them after 30m. were brushed with a camel-hair brush, like the leaves in the solution of camphor, but this produced no effect. * See Dr. M. Traube's curious experiments on the production of artificial cells, and on their permeability to various salts, described in his papers: '' Experimente zur 'l'heorie der Zellenbildung und Endosmose," Breslau, L866 ; and " Experimente zur physicalischen Erkhi.rung dor Bildung der Zellhaut, ihres Wachsthums durch Intussusception," Breslau, 1874. These researches perhaps explain my results. Dr. Traube commonly employed as a membrane the precipitate formed when tannic acid comes into contact with a solution of gelatine. By allowing a precipitation of sulphate of barium to take pbee at the same time, tho membrane becomes "infiltrated" with this salt; and in conscq uence of the intercalation of molecules of sulphate of barium among those of the gelatine precipitate, tho molecular interstices in the membrane are made smaller. In this altered condition, the membrane no longer allows the passage through it of either sulphate of ammonia or nitrate of barium, though it retains its permeability for water and chloride of ammonia. CHAP. IX. VAPOUR OF CllLOROFORM. 217 Nor did the c four leaves, on being left for 24 hrs. in the diluted alcohol, undergo any inflection. They were then removed; one being placed in an infu. ion of raw meat, and bits of meat on the discs of the other three, with their stalk. in water. Next day one seemed a little injured, whilst two others showed mer ly a trace of inflection. We must, however, bear in mind that immersion for 2± lus. in water prevents lcav s from cla ping meat. Hence alcohol of the above strength is not poisonous, nor does it stimulate the leaves like camphor does. The vapour of alcohol acts differently. A plant having three good leaves was left for 25 m. under a receiver holding 1~ oz. with sixty minims of alcohol in a watch-glass. No movement ensued, but some few of the glands were blackened and shrivelled, whilst many became quite pale. These were. sc~ttored over all tho leaves in the most inegular manner, rcmmdmg me of the manner in which tho glands were affected by the vapour of carbonate of ammonia. Immediately on the removal of the receiver particles of raw meat were placed on many of the glands, those which retained thciT proper colour being chiefly selected. But not a single tentacle was inflected during the next 4 hrs. After the first 2 hrs. the glands on all the tentacles began to dry; and next morning, after 22 hrs., all three leaves appeaTcd almost dead, with their glands dry ; the tentacles on one leaf alone beillg partially inflected. . A second plant was left for only 5 m. with some alcohol In a watch-glass, under a 12-oz. receiver, and particles of meat were then placed on the glands of several tentacles. After 10 m. some of them began to curve inwards, aDd after 55 m. nearly all were considerably inflected ; but a few did not move. Somo anresthetbic effect is here probable, but by no means certain. A third plant was also left for 5 m. under the same small vessel, with its whole inner surface wetted with about a dozen drops of alcohol. Particles of meat were now placed on the glands of several tentacles, some of which first began to move in 25m.; after 40 m. most of them were somewhat inflected, and after I hr. 10m. almost all were considerably inflected. From their slow rate of movement there can be no doubt that tho glands of these tentacles had been rendered insensible for a time by exposure during 5 m. to the vapour of alcohol. Vapour of Chloroform.-Tho action of this vapo~r o~ Drosera is very variable, depending, I suppose, on the constitutiOn o~ age of the plant, or on some unknown condition. It s.o~etimes causes tho tentacles to move with extraordinary rapidity, and sometimes produces no such effect. The glands are sometimes |
