Obrazy na stronie
PDF
ePub

summer, and, with less energy, fines of the animal and vegetable because with less prodigality of kingdoms, when all the while specimens, during the autumn and Nature knows of no such demarcatwinter at home. In the present state of knowledge, the independent observations of every one who has had any experience cannot but be welcome.

ing lines. The Animal does not exist; nor does the Vegetable: both are abstractions, general terms, such as Virtue, Goodness, Colour, used to designate certain groups of partiIt must be assumed at starting culars, but having only a mental that the reader knows what a Sea existence. Who has been fortunate Anemone is, in aspect at least. No enough to see the Animal? We description will avail, in default of have seen cows, cats, jackasses, and direct observation; even pictures so camelopards; but the "rare monster" admirable as those in Mr. Tugwell's Animal is visible in no menagerie. charming little book,* only give an If you are tempted to call this metaapproximate idea; while to those physical trifling, I beg you to read who have seen neither picture nor the discussions published on the animal it will be of little use to de- vegetable or animal nature of Diatoclare that the "Actinia is a fleshy maceæ, Volvocinæ, &c., or to attend cylinder, attached by one extremity to what is said in any text-book on to a rock, while the free end is sur- the distinctions between animals and mounted by numerous tentacula vegetables, and you will then see arranged in several rows, which, there is something more than metawhen expanded, give the animal the phisics in my paradox. In the appearance of a flower." Assuming then that you know the general aspect of the Actinia, you may follow my description of the animal's bearing and habits. How do I know that it is an animal, and not a flower, which it so much resembles? Well, to be perfectly candid, I do not know it. Nobody does. No one yet has been able to distinguish, in the face of severe critical precision, between the animal and plantorganisation, so as to be able authoritatively to say, "This is exclusively Now what are the characteristic animal." To distinguish a cow from marks of the Sea Anemone, which a cucumber requires, indeed, no pro- entitle it to be removed from the found inauguration into biological hands of the botanist, and placed in mysteries; we can "venture fearlessly those of the zoologist? Rymer Jones to assert" (with that utterly uncalled- assures us, that its animal nature "is for temerity exhibited by bad writers soon rendered evident," and he thinks in cases when no peril whatever is this evidence is the manifestation of hanging over the assertion) that the sensibility. "A cloud veiling the cow and cucumber are not allied- sun will cause their tentacles to fold no common parentage links them to- as though apprehensive of danger gether, even through remote relation- from the passing shadows." Unship; but to say what is an animal, happily, the fact alleged is a pure presupposes a knowledge of what fiction; and, were it true, would not is essentially and exclusively ani- distinguish the Actinia from those mal; and this knowledge unhappily plants which close their petals when has never yet been reached. Much the sun goes down. A fiction, howhot, and not wise, discussion has ever, it is, as any one may verify. occupied the hours of philosophers in If Actiniæ have been seen to fold up trying to map out the distinct con- their tentacles when a cloud has

simpler organisms there is no mark which can absolutely distinguish the animal from the vegetable; and if in the higher organisms a greater amount of characteristic differences may be traced, so that we may, for purposes of convenience, consider a certain group of indications as entitling the object to be classed under the Animal division, we must never forget that such classifications are purely arbitrary, and as the philosophers say-subjective.

*A Manual of the Sea Anemones commonly found on the English Coast. By the Rev. GEORGE TUGWELL.

1856.

passed before the sun, this has been much in the same way as plants a coincidence, not a causal relation; assimilate the organic material difso far from light being the necessary fused through the soil and atmoscondition of their expansion, they are phere. Filter the water carefully, in perfect expansion in the darkness; and remove from it all growing vegeand if the venturous naturalist will tation, and you will find the animal imitate Mr. Tugwell, and, with the fasting, but speedily dying, however solemn chimes of midnight as accom- freely oxygen may be supplied. It paniment, take his lantern on the is on this account that when we rocks, he will find all the Anemones make artificial sea-water, it is nein full blossom. Then again, al- cessary to allow alga to grow in it though the Anemone entraps its prey, for some two or three weeks before or anything else that may come in putting in the animals; by which time contact with it tentacles, this is no the water has become charged with proof of animality, for the sensitive organic material. plant, known as the Flytrap of Venus Mere sensibility and capture of (Dionea muscipula), has a precisely food, therefore, are not the distinanalogous power; any insect, touch- guishing marks we seek, since the ing the sensitive hairs on the surface plant is found to possess them as of its leaf, instantly causes the leaf to perfectly as the animal. Is spontashut up and enclose the insect, as in neous locomotion a sufficient mark? a trap; nor is this all: a mucilagin- No; and for these two reasons: ous secretion acts like a gastric juice Some animals have no such power; on the captive, digests it, and ren- some plants, and all spores, have it. ders it assimilable by the plant, There are animals which no botanist which thus feeds on the victim, as has ever claimed-the Ascidians, for the Actinia feeds on the annelid or example, which can scarcely be said crustacean it may entrap. Where, to exhibit any motion at all (the then, is the difference? Neither seeks rhythmic contraction and expansion of its food place the food within a their orifices not deserving the name,) line's breadth of the tentacles, or while their whole lives are spent rootsensitive hairs, and so long as actual ed to the rock or shell, as firmly contact is avoided, the grasping of as the plant is rooted in the earth. the food will not take place. But Nay, even with regard to the aneyou object, perhaps, that this mode mones, it is said by Dr. Landsof feeding is normal with the Actinia, borough, Dr. Carpenter, and others, exceptional with the Flytrap. The that they will not move towards the plant, you say, is nourished by the water, should the vessel be gradually earth and air, the animal depends on emptied, or the water evaporate, not what it can secure. I must contra- even if their tentacles can reach its surdict you; indeed I must, although face. This is incorrect; but I mention with the profoundest respect. For it as one of the difficulties which granting what, in fact, I sturdily would meet the student in the way of dispute that the Flytrap is in no distinguishing the anemone from way dependent upon such insect food plants. It is one of the many inacas may fall into its clutch, we shall curate statements, grounded on imperstill observe the Actinia in similar fect observation, which are repeated independence. Keep the water free in hand-books. The original obfrom all visible food, and the Actiniæ server probably noticed an anemone continue to flourish and propagate some time out of the water, making no just as if they daily clutched an un- effort to return; had the observation happy worm. The fact is well been continued, the doubt would have known, and is currently, but errone- been solved. Some anemones, especiously, adduced as illustration of the ally the common smooth species (Meanimal's power of fasting. But there sembryanthemum) are accustomed is no fasting in the matter. In this daily to be left out of water by the water free from visible aliment there receding tide, so that in captivity they is abundance of invisible aliment, may be supposed rather to enjoy an infusoria, spores, organic particles, occasional air-bath. I have repeatedly &c., which the animal assimilates, seen mine crawl out of the water,

[ocr errors]
[ocr errors]

and settle on the edge of the glass or pan, high and dry; but they descended again after a few hours. The locomotion of the anemones is, however, various in various species. I do not think the "Trogs' ever move; nor do the "Gems seem migratory; but the "Antheas" and the "Smooths" are somewhat restless. "The Actiniæ,” says Rymer Jones, "possess the power of changing their position; they often elongate their bodies, and, remaining fixed by the base, stretch from side to side, as if seeking food at a distance; they can even change their place by gliding upon the disc that supports them, or detaching themselves entirely, and swelling themselves with water, they become nearly of the same specific gravity as the element they inhabit, and the least agitation is sufficient to drive them elsewhere. Reaumur even asserts, that they can turn themselves so as to use their tentacles as feet, crawling upon the bottom of the sea; but this mode of progression has not been observed by subsequent naturalists." Yes, Dr. Johnston once saw it; I also witnessed an Anthea moving thus; but I suspect it is only the Anthea which has the power, and this it probably owes to its more solid tentacles.

Again the question recurs, How then do we know the anemone to be an animal? in other words, what characteristic marks guide zoologists in classing it in that division? I really know of none but purely anatomical marks.* These however, suftice, and if you please we will continue to speak of the anemone as an animal, and, what is more, a very carnivorous animal, eating most things that come within reach, from limpets to worms, from fish to roast beef. It has even a reputation for voracity,

not to say gourmandise; in the matter of shell-fish it would put even Dando to the blush. Dr. Johnston in his valuable History of British Zoophytes relates this anecdote (which you are not bound to believe): "I had once brought to me a specimen of Actinia crassicornis that might originally have been two inches in diameter, and that had somehow contrived to swallow a valve of Pecten maximus of the size of an ordinary saucer. The shell fixed within the stomach was so placed as to divide it completely into two halves, so that the body stretched tensely over had become thin and flattened like a pancake. All communication between the inferior portion of the stomach and the mouth was of course prevented; yet instead of emaciating and dying of an atrophy, the animal had availed itself of what had undoubtedly been a very untoward accident, to increase its enjoyments and its chance of double fare. A new mouth furnished with two rows of numerous tentacles was opened upon what had been the base, and led to the under stomachthe individual had become a sort of Siamese Twin, but with greater intimacy and extent in its unions." Such is the blind voracity of this animal, that anything and everything is carried straightway into its stomach to be there tried, and rejected only on proved indigestibility. Oue day, while sorting and distributing to their respective jars the animals captured during the morning's hunt, I was called into the balcony by the agitated entreaties of lovely Sixteen, exclaiming, "Oh,.do come Mr. Contributor! do come, and rescue this green anemone from a great nasty beetle." I went to the rescue, and found a large beetle struggling in the clutches of a green,

*It is unnecessary to particularise these anatomical marks, which will occur to the mind of every student, as belonging exclusively to that division of animated beings which manifest the group of phenomena baptised by the name of Animality. Wherever you find muscular tissue, or an alimentary canal, you are absolutely certain that nothing belonging to the vegetable kingdom is before you. In function there is often considerable resemblance between Plant and Animal; but in structure the differences early manifest themselves, growing greater as the scale ascends. Although, therefore, at the bottom of the scale no distinguished characteristic isolates animals from plants, as we ascend the scale we find many definite marks by which the two groups may be known.

Anthea not much larger than himself. "The beetle is the victim," I quietly told Sixteen, who, not having profound sympathies with beetles, was pacified as she saw the struggling insect slowly passing into the stomach of the Anthea, his struggles growing fainter and fainter, and finally ceasing altogether, till at last we saw him with head and thorax engulphed in the ravenous maw, his abdomen sticking up in the air.

A question of great interest and some intricacy here presents itself: Was the beetle paralysed by some peculiar poison secreted from the tentacles of the anemone? a question which opens into this wider one Have the polypes the mysterious power, almost universally attributed to them, of paralysing with a touch the victims they may grasp, so that, should the victim escape from the grasp, it is only to die presently from the fatal touch? The powers of fascination possessed by some animals, of poisoning possessed by others, of electrical discharges possessed by others, naturally lead men to interpret certain observations made on the polypes, as proofs that they, too, possess some such power; and this suggestion gains a more ready credence from the tendency in most minds to welcome every unexplained phenomenon as indicating an occult cause. This witch-like power of fascination, this power of paralysing with a touch, appeals to our imagination, and gains easy access to belief. But the spirit of scientific scepticism forces me to declare that as far as my observations and experiments extend, there is nothing like evidence in favour of this power, much evidence against it. Some anemones certainly appear to sting-as some jelly-fish sting-although the majority have no such effect upon our hands, which every one knows who has handled them. I never perceived this stinging sensation myself; and Dr. Landsborough says: "From my own experience I can say nothing as to this stinging power; for though I have handled not only the commoner Actiniæ, but also the larger and less common Anthea, I never felt any

thing approaching to stinging; but I never touched a tentaculum without perceiving the tip of it had some prehensile property by which it took a slight hold of the skin of the finger, causing a kind of rasping feeling when withdrawn. It may be, however, that the fangs had not fair play with my fingers, if somehow or other they are sting-proof."* He then makes the following quotation from Mrs. Pratt's Chapters on the Common Things of the Sea-side, which I reproduce as positive and direct testimony: "It appears that different persons are variously affected even by touching the same Actiniæ. The author had placed in a vessel of sea-water a fine specimen of the fig marigold seaanemone, which she was accustomed to touch many times during the day. The tentacula closed immediately round the intruding finger,_producing only a slight tingling. Her surprise was great at finding that the same anemone, on being touched by another person, communicated a more powerful sensation, which her friend assured her was felt up the whole of the arm. More than twenty persons touched this anemone; and the writer was amused by observing how variously they were affected, some being only slightly tingled, while others started back as if stung by a nettle." I think, in the face of testimony so precise as this, we may waive all negative evidence, and accept the fact of stinging as proven. But now comes the question: Is this stinging produced by poison vesicles and spicula, as the great majority of writers maintain; or is it no more poisonous than the pricking of a thorn?

Those who maintain the former opinion, explain by it the alleged cases of paralysis exhibited by the animals which have escaped in the struggle; and the incident just related of the beetle killed, but not swallowed (he was too large for that), seems entirely to favour such a

conclusion. Nevertheless, from subsequent investigations I am led to oppose the opinion in toto. Sir John Dalyell-one of the best authorities-thinks that the anemone conquers its prey by mere strength,

* Popular History of British Zoophytes, p. 239.

[ocr errors]

and not by any poisonous fluid. He of all the anemones, and the only is somewhat exaggerated, however, one which seems to sting; but the in the statement of his opinion. crab was too active, or too little "Nothing," he says, can escape appetising: he got away as before. their deadly touch. Every animated I tried another Anthea and a Daisy being that comes in slightest con- (Actinia bellis), but with the same tact is instantly caught, retained, result. In each case the crab was and mercilessly devoured." This is clutched, but in each case he got mere rhetoric animals, even such away unhurt. I then chose another as form their natural prey, con- crab, not more than half the size of stantly touch the tentacles nay, the former, and certainly no match are even caught, and yet escape. in point of strength for the anemone, "Neither strength nor size, nor the yet after being embraced and carried resistance of the victim, can daunt to the mouth, I observed the crab the ravenous captor. It will readily slowly appear from the unfolding grasp an animal which, if endowed tentacles, and scuttle away with with similar strength, advantage, great activity. and resolution, could certainly rend its body asunder. It is in the highest degree carnivorous. Thence do all the varieties of the smaller finny tribes, the fiercest of the crustacea, the whole vermicular race, and the softer tenants among the testacea, fall a prey to the Actiniæ." One is astonished to meet with such a passage from so accurate an observer. It is pure exaggeration, which succeeding writers have accepted as literal truth. Thus, Rymer Jones assures the student that "no sooner are the tentacles touched by a passing animal, than it is seized and held with unfailing pertinacity." Had the professor watched anemones he would know that, so far from the grasp being "unfailing," it as often fails as succeeds, when the captive is of tolerable activity; and very noticeable is the fact, that when the animals escape, they escape unhurt: a fact in direct contradiction to the belief in a poison secreted by the tentacles. On the 19th June 1856 I resolved to bring this question to the test, and dropped a tiny crab, rather smaller than a fourpenny piece, on the tentacles of my largest Crassicornis (nearly as large as a glass tumbler). He was clutched at once, and the tentacles began to close round him; he struggled vigorously, and freed bimself after a few seconds. Placed there a second time, he again got away. I waited to see if any symptoms of paralysis would declare themselves after this contact, but he was as lively as ever. Later in the day I placed him on the tentacles of the voracious Anthea, the most powerful

This experiment casts a doubt on what is asserted by all writers, namely, that anemones feed on crabs-Rymer Jones actually recording that "they will devour a crab as large as a hen's egg." Has any one ever seen a live crab caught and eaten by an anemone? I confess never to have seen it, and the experiment just related disposes me to doubt: although it is quite possible that my aremones were dainty, because not hungry, and refused food which, under less epicurean conditions, would have been welcome. If any one has seen the anemone feeding on live crabs, it would be thus that my observation could be explained. Meanwhile I think it right to propound the doubt, and to add to it this subsequent observation made on the 3d of August: I took a tiny crustacean, of the shrimp family, about half an inch in length, and dropped it in a vase containing some Daisies. It soon touched the tentacles of one of these, was drawn in, but almost immediately escaped. It then swam about until it touched the largest Daisy, and was quickly engulfed. As it had entirely disappeared, I expected it would be certainly killed if not eaten, but in a few moments it made its way out unhurt, and swam away. These Daisies had not been fed for at least a fortnight; they had subsisted entirely on the invisible aliment floating in the water; yet they either could not, or would not, eat this crustacean.

On the question of food we may withhold our opinion till some more

« PoprzedniaDalej »