* 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 Theorie der Zellenbildung und Endosmose,” Breslau, 1866; and “Experimente zur physicalischen Erklrung der 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 place at the same time, the membrane becomes “infiltrated” with this salt; and in consequence of the intercalation of molecules of sulphate of barium among those of the gelatine precipitate, the 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. [page 217]
Nor did these four leaves, on being left for 24 hrs. in the diluted alcohol, undergo any inflection. They were then removed; one being placed in an infusion of raw meat, and bits of meat on the discs of the other three, with their stalks in water. Next day one seemed a little injured, whilst two others showed merely a trace of inflection. We must, however, bear in mind that immersion for 24 hrs. in water prevents leaves from clasping 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 19 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 scattered over all the leaves in the most irregular manner, reminding me of the manner in which the 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 their 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 appeared almost dead, with their glands dry; the tentacles on one leaf alone being 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, and after 55 m. nearly all were considerably inflected; but a few did not move. Some anaesthetic 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 25 m.; after 40 m. most of them were somewhat inflected, and after 1 hr. 10 m. almost all were considerably inflected. From their slow rate of movement there can be no doubt that the glands of these tentacles had been rendered insensible for a time by exposure during 5 m. to the vapour of alcohol.
Vapour of Chloroform.—The action of this vapour on Drosera is very variable, depending, I suppose, on the constitution or age of the plant, or on some unknown condition. It sometimes causes the tentacles to move with extraordinary rapidity, and sometimes produces no such effect. The glands are sometimes [page 218] rendered for a time insensible to the action of raw meat, but sometimes are not thus affected, or in a very slight degree. A plant recovers from a small dose, but is easily killed by a larger one.
A plant was left for 30 m. under a bell-glass holding 19 fluid oz. (539.6 ml.) with eight drops of chloroform, and before the cover was removed, most of the tentacles became much inflected, though they did not reach the centre. After the cover was removed, bits of meat were placed on the glands of several of the somewhat incurved tentacles; these glands were found much blackened after 6 hrs. 30 m., but no further movement ensued. After 24 hrs. the leaves appeared almost dead.
A smaller bell-glass, holding 12 fluid oz. (340.8 ml.), was now employed, and a plant was left for 90 s. under it, with only two drops of chloroform. Immediately on the removal of the glass all the tentacles curved inwards so as to stand perpendicularly up; and some of them could actually be seen moving with extraordinary quickness by little starts, and therefore in an unnatural manner; but they never reached the centre. After 22 hrs. they fully re-expanded, and on meat being placed on their glands, or when roughly touched by a needle, they promptly became inflected; so that these leaves had not been in the least injured.
Another plant was placed under the same small bell-glass with three drops of chloroform, and before two minutes had elapsed, the tentacles began to curl inwards with rapid little jerks. The glass was then removed, and in the course of two or three additional minutes almost every tentacle reached the centre. On several other occasions the vapour did not excite any movement of this kind.
There seems also to be great variability in the degree and manner in which chloroform renders the glands insensible to the subsequent action of meat. In the plant last referred to, which had been exposed for 2 m. to three drops of chloroform, some few tentacles curved up only to a perpendicular position, and particles of meat were placed on their glands; this caused them in 5 m. to begin moving, but they moved so slowly that they did not reach the centre until 1 hr. 30 m. had elapsed. Another plant was similarly exposed, that is, for 2 m. to three drops of chloroform, and on particles of meat being placed on the glands of several tentacles, which had curved up into a perpendicular position, one of these began to bend in 8 m., but afterwards moved very slowly; whilst none of the other tentacles [page 219] moved for the next 40 m. Nevertheless, in 1 hr. 45 m. from the time when the bits of meat had been given, all the tentacles reached the centre. In this case some slight anaesthetic effect apparently had been produced. On the following day the plant had perfectly recovered.
Another plant bearing two leaves was exposed for 2 m. under the 19-oz. vessel to two drops of chloroform; it was then taken out and examined; again exposed for 2 m. to two drops; taken out, and re-exposed for 3 m. to three drops; so that altogether it was exposed alternately to the air and during 7 m. to the vapour of seven drops of chloroform. Bits of meat were now placed on thirteen glands on the two leaves. On one of these leaves, a single tentacle first began moving in 40 m., and two others in 54 m. On the second leaf some tentacles first moved in 1 hr. 11 m. After 2 hrs. many tentacles on both leaves were inflected; but none had reached the centre within this time. In this case there could not be the least doubt that the chloroform had exerted an anaesthetic influence on the leaves.