Augtist 21, 1879] 



NATURE 



591 



in this fact we have another striking point of resemblance 

 between them and plants. 



A similar approximation of the two organic kingdoms has 

 been shown by the beautiful researches of Mr. Darwin — con- 

 firmed and extended by his son, Mr. Francis Darwin — on Drosera 

 and other so-called carnivorous plants. These researches, as is 

 now well known, have shown that in all carnivorous plants thera 

 is a mechanism fitted for the capture of living prey, and that the 

 animal matter of the prey is absorbed by the plant after having 

 been digested by a secretion which acts like the gastric juice of 

 animals. 



Again, Niigeli has recently shown ^ that the cell of the yeast 

 fungus contains about 2 per cent, of peptine, a substance 

 hitherto known only as a product of the digestion of azotised 

 matter by animals. 



Indeed, all recent research has been bringing out in a more 

 and more decisive manner the fact that there is no dualism in 

 life, — that the life of the animal and the life of the plant are, 

 like their protoplasm, in all essential points identical. 



But there is, perhaps, nothing which shows more strikingly the 

 identity of the protoplasm in plants and animals, and the absence 

 of any deep-pervading difference between the life of the animal 

 and that of the plant, than the fact that plants may be placed, 

 just like animals, under the influence of anaesthetics. 



When the vapour of chloroform or of ether is inhaled by the 

 human subject, it passes into the lungs, where it is absorbed by 

 the blood, and thence carried by the circulation to all the tissues 

 of the body. The first to be affected by it is the delicate nervous 

 element of the brain, and loss of consciousness is the result. If 

 the action of the ancesthetic be continued, all the other tissues are 

 in their turn attacked by it and their irritability arrested. A set 

 of phenomena entu-ely parallel to these may be presented by 

 plants. 



We owe to Claude Bernard a series of interesting and most 

 isstructive experiments on the action of ether and chloroform on 

 plants. He exposed to the vapour of ether a healthy and vigo- 

 rous sensitive plant, by confining it under a bell-glass into which 

 he introduced a sponge filled with ether. At the end of half 

 an hour the plant was in a state of anaesthesia, all its leaflets 

 remained fully extended, but they showed no tendency to shrink 

 when touched. It was then withdrawn from the influence of 

 the ether, when it gradually recovered its irritability, and finally 

 responded, as before, to the touch. 



It is obvious that the irritability of the protoplasm was here 

 arrested by the anaesthetic, so that the plant became unable to 

 give a response to the action of an external stimulus. 



It is not, however, the irritability of the protoplasm of only 

 the motor elements of plants that anaesthetics are capable of 

 arresting. These may act also qn the protoplasm of those cells 

 whose function lies in chemical synthesis, such as is manifestsd 

 in the phenomena of the germiijation of the seed and in nutrilion 

 generally, and Claude Bernard has shown that germination is 

 suspended by the action of ether or chloroform. 



Seeds of cress, a plant whose germination is very rapid, were 

 placed in conditions favourable to a speedy germination, and 

 while thus placed were exposed to the vapour of ether. The 

 germination, which would otherwise have shown itself by the 

 next day, was arrested. For five or six days the seeds were 

 kept under the influence of the ether, and showed during this 

 time no disposition to germinate. They were not killed, how- 

 ever, they only slept, for on the substitution of common air for 

 the etherised air witli which they had been surrounded, germi- 

 nation at once set in and proceeded with activity. 



Experiments were also made on tliat function of plants by 

 which they absorb carbonic acid and exhale oxygen, and which, 

 as we have already seen, is carried on through the agency of 

 the green protoplasm or chlorophyll, under the influence of light 

 —a function which is commonly, but erroneously, called the 

 respiration of plants. 



Aquatic plants afford the most convenient subjects for such 

 experiments. If one of these be placed in a jar of water holding 

 ether or chloroform in solution, and a bell-glass be placed ove" 

 the submerged plant, we shall find that the plant no longer 

 absorbs carbonic acid or emits oxygen. It remains, however, 

 quite green and healthy. In order to awaken the plant, it is 

 only necessary to place it in non-etherised water, when it will 

 begin once more to absorb carbonic acid, and exhale oxygen 

 under the influence of sunlight. 



' "Ueber die chcmische Zu5.immen5etzung der Hefe," Silzungsitricht 

 dtr math. phys. Classe der k.k. Akad. dtr Wiisem. zu IMnchtn, 1878. 



The same great physiologist has also investigated the action 

 of anaesthetics on fermentation. It is well known that alcoholic 

 fermentation is due to the presence of a minute fungus, the yeast 

 fungus, the living protoplasm of whose cells has the property of 

 separating solutions of sugar into alcohol, which remains in the 

 liquid, and carbonic acid, which escapes into the air. 



Now, if the yeast plant be placed along with sugar in 

 etherised water it will no longer act as a ferment. It is 

 anaesthesiated, and cannot respond to the stimulus which, under 

 ordinary circumstances, it would find in the presence of the sugar. 

 If, now, it be placed on a filter, and the ether washed com- 

 pletely away, it will, on restoration to a saccharine liquid, soon 

 resume its duty of separating the sugar into alcohol and car- 

 bonic acid. 



Claude Bernard has further called attention to a very signi- 

 ficant fact which is observable in this experiment. While the 

 proper alcoholic fermentation is entirely arrested by the etherisa- 

 tion of the yeast plant, there still goes on in the saccharine solution 

 a curious chemical change, the cane sugar of the solution being 

 converted into grape sugar, a substance identical in I its chemical 

 composition with the cane sugar, but different in its molecular 

 constitution. Now it is well known from the researches of 

 Bertholet that this conversion of cane sugar into grape sugar is 

 due to a peculiar inversive ferment, which, while it accompanies 

 the living yeast plant, is itself soluble and destitute of life. 

 Indeed it has been shown that in its natural conditions the yeast 

 fungus is unable of itself to assimilate cane sugar, and that in 

 order tliat this may be brought into a state fitted for the 

 nutrition of the fungus, it must be first digested and converted 

 into grape sugar, exactly as happens in our own digestive organs. 

 To quote Claude Bernard's graphic account : — 



" The fungus ferment has thus beside it in the same yeast a 

 sort of servant given by nature to effect this digestion. The 

 servant is the unorganised inversive ferment. This ferment is 

 soluble, and as it is not a plant, but an unorganised body 

 destitute of sensibility, it has not gone to sleep under the action 

 of the ether, and thus continues to fulfil its task." 



In the experiment already recorded on the germination of 

 seeds the interest is by no means confined to that which attaches 

 itself to the arrest of the organising functions of the seed, those 

 namely which manifest themselves in the development of the 

 radicle and plumule and other org.ins of the young plant. 

 Another phenomenon of great significance becomes at the same 

 time apparent — the anaesthetic exerts no action on the con- 

 comitant chemical phenomena which in germinating seeds show 

 themselves in the transformation of starch into sugar under the 

 influence of diastase (a soluble and non-living ferment which 

 also exists in the seed), and the absorption of oxygen with the 

 exhalation of carbonic acid. These go on as usual, the 

 anaesthesiated seed continuing to respire, as proved by the 

 accumulation of carbonic acid in the surrounding air. The 

 presence of the carbonic acid was rendered evident by placing 

 in the same vessel with the seeds which were the object of the 

 experiment, ra solution of barytes, when the carbonate became 

 precipitated from the solution in quantity equal to that produced 

 in a similar experiment with seeds germinating in unetherised air. 

 So, also in the experiment which proves the faculty possessed 

 by the chlorophyllian cells of absorbing carbonic acid and exhaling 

 oxygen under the influence of light may be arrested by anaesthetics, 

 it could be seen that the plant, while in a state of anaesthesia, 

 continued to respire in the manner of animals ; that is, it con- 

 tinued to absorb oxygen and exhale carbonic acid. This is the 

 true respiratory function which was previously masked by the 

 predominant function of assimilation, which devolves on the 

 green cells of plants, and which manifests itself under the 

 influence of light in the absorption of carbonic acid and the 

 exhalation of oxygen. 



It must not, however, be supposed that the respiration of 

 plants is entirely independent of life. The conditions which 

 bring the oxygen of the air and the combustible matter of the 

 respiring plant into such relations as may allow them to act on 

 one another are still under its control, and we must conclude 

 that in Claude Bernard's experiment the anaesthesia had not been 

 carried so far as to .arrest such properties of the living tissues as 

 are needed for this. 



The quite recent researches of Schiitzenberger, who has in- 

 vestigated the process of respiration as it takes place in the cell 

 of the yeast fungus, have shown that vitality is a factor in this 

 process. He has shown that fresh yeast, placed in water, breathes 

 like an aquatic animal, disengaging carbonic acid, and causing 



