Imágenes de páginas
PDF
EPUB

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 This experiment casts a doubt its body asunder. It is in the high- on what is asserted by all writers, est degree carnivorous. Thence do namely, that anemones feed on all the varieties of the smaller finny crabs — Rymer Jones actually retribes, the fiercest of the crustacea, cording that “they will devour a the whole vermicular race, and the crab as large as a hen's egg.” Has softer tenants among the testacea, any one ever seen a live crab caught fall a prey to the Actiniæ.” One is and eaten by an anemone ? I confess astonished to meet with such a pas- never to have seen it, and the exsage from so accurate an observer. periment just related disposes me It is pure exaggeration, which suc- to doubt: although it is quite possible ceeding writers have accepted as that my anemones were dainty, beliteral truth. Thus, Rymer Jones cause not hungry, and refused 'food assures the student that “no sooner which, under less epicurean condiare the tentacles touched by a pass- tions, would have been welcome. If ing animal, than it is seized and held any one has seen the anemone feedwith unfailing pertinacity.” Had the ing on live crabs, it would be thus professor watched anemones he would that my observation could be exknow that, so far from the grasp plained. Meanwhile I think it right being “unfailing," it as often fails to propound the doubt, and to add as succeeds, when the captive is of to it this subsequent observation tolerable activity; and very notice- made on the 3d of August : I took a able is the fact, that when the ani- tiny crustacean, of the shrimp famimals escape, they escape unhurt: a ly, about half an inch in length, and fact in direct contradiction to the dropped it in a vase containing belief in a poison secreted by the some Daisies. It soon touched the tentacles. On the 19th June 1856 tentacles of one of these, was drawn I resolved to bring this question to in, but almost immediately escaped, the test, and dropped a tiny crab, It then swam about until it touched rather smaller than a fourpenny piece, the largest Daisy, and was quickly on the tentacles of my largest Crassi- engulfed. As it had entirely diseornis (nearly as large as a glass tum- appeared, I expected it would be bler). He was clutched at once, and the certainly killed if not eaten, but in tentacles began to close round him; a few moments it made its way out he struggled vigorously, and freed unhurt, and swam away. These himself after a few seconds. Placed Daisies had not been fed for at least there a second time, he again got a fortnight; they had subsisted enaway. I waited to see if any symp- tirely on the invisible aliment floattoms of paralysis would declare them- ing in the water; yet they either selves after this contact, but he was could not, or would not, eat this as lively as ever. Later in the day crustacean. I placed him on the tentacles of the On the question of food we may voracious Anthea, the most powerful withhold our opinion till some more decisive evidence is adduced; but time held by the tentacle of the on the question of the paralysing hydra; and after intently watching power said to reside in the ten- them, saw them at last swim away tacles, these experiments surely de- again lively as before. I removed a termine a negative. In spite of hydra from the phial, in a little the beetle, so completely vanquished, water, and placing it on a slip of there is the evidence of two crabs glass, allowed it to settle and expand and a shrimp being in repeated con- there for two hours, when I added tact with the tentacles, and in nowise several water-fleas (Cyprido) to the affected.

little pond, and patiently watched While preparing these notes for the them swimming to and fro. Repress, I have been led to extend the peatedly they touched the tentacles experiments; because, although it in their course, but were not hurt, would by no means necessarily fol- were not arrested. At length one low that whatever was true of the was caught, and held for some hydroid polypes must also be true of seconds ; it then fell to the bottom, the anemones, yet a very plausible and remained motionless for at least suspicion might arise—and did in- two minutes, after which it started deed arise in my mind — throwing up, and was off as if its course had doubt on results which were in never been arrested. Now came the contradiction to what was reported test. With a needle I gently arrested of the fresh-water polypes. Read one of these water-fleas; it suddenly this passage from the last edition of sank motionless, remained thus for Owen's Lectures, bearing the date more than a minute, and then darted 1855: "That the tentacula have the off again. Thrice I repeated this power of communicating some be- act, and each time with similar numbing or noxious influence to the result. Will any one say the needle living animals which constitute the had a benumbing poison which was food of the hydra, is evident from secreted when the animal came in the effect produced, for example, contact with it? And does not the upon an entomostracan, which may reader at once recognise in this sudhave been touched, but not seized, by den motionlessness of the animal a one of these organs. The little active very familiar phenomenon? The spider, crustacean is arrested in the midst of the crab, the oniscus, and very many its rapid darting motion, and sinks animals' sham dead," as "schoolapparently lifeless for some distance; boys know, when danger threatens ; then slowly recovers itself, and re- these water-fleas "sham dead” when sumes its ordinary movements. Sie- the polype or the needle touches bold states, that when a Naïs, a them. I might have rested my inDaphnia, or the larva of a Cheiro- credulity of the alleged paralysing nomus, have been wounded by the influence on this one experiment; but darts, they do not recover, but die. I confirmed it in other ways. DropThese and other active inhabi- ping the larva of an ephemeron into tants of fresh waters, whose powers the phial containing my hydræ, I should be equivalent to rend asunder observed it thrice caught by three the delicate gelatinous arms of their different hydræ; it did not sham low-organised captor, seem paralysed dead,” but tore itself away without almost immediately after they have visible hurt. Nay, I also observed been seized, and so countenance the one of those animalcules known as opinion of Corda, that the secretion paste-eels” for some time in conof a poison enters the wounds.” tact with the tentacle of a hydra, Such statements can only be set on the stage of the microscope, but, aside by direct experiment; and the in spite of its having no shell to superiority of experiment over mere protect it from the poison, it was observation needs no argument. As unhurt by the contact. Not having a matter of observation, I too had a Naïs, I could not test what Siebold been struck with the fact noticed by says of it; but what has already Owen. I saw the tiny water-fleas been mentioned must, I think, sufdrop apparently lifeless to the bot- fice to convince the reader that the tom of the phial, after being some current opinion is an error, founded

[graphic]

on observation unverified by experi- a whole Encyclopædia, and is so ment. Had I trusted to observation obliging as to retail many pages of it alone, I too should have believed freely in her conversation. Besides, the current opinion; it was only by if the monotony of the anemone verification, according to the de- wearies you, there is always this mands of inductive scepticism, that variety in reserve : you can eat it! the error became obvious. *

The Italians do ; they boil it in sea" But do tell us something about water with great satisfaction. Thus the habits and instincts of these boiled, it has “ a shivering texture anemones," some light-minded reader somewhat like calf's-foot jelly; the suggests, impatient of all discussion, smell is somewhat like that of a and supremely indifferent to all con- warm crab or lobster,” and it is eaten siderations save those of a moral with savoury sauce. Mr Gosse deorder. Unhappily my story is not scribes his frying them in butter, if ampler in detail, nor finer in com- I remember rightly; and although plexity of movement, than the story he felt a little difficulty in swallowof Canning's “Knife-grinder"—who ing the first mouthful-probably rehad none to tell. The anemone is morse and zoological tenderness gave lovely, but even its warmest ad- him what the Italians call a knot mirers must confess it is a little in the throat”-yet, having vanmonotonous in its manifestations. quished his scruples, he ate with Existence suffices it. It expands its some relish. Lady Jane is “horrified" coronal of tentacles, eats when chance at the idea of eating her pets ; but favours it, produces offspring, which now that horse-fesh is publicly sold it sends forth, leaving it,

in the markets of Vienna and other πολλοις διαυλοις κυματων φορουμενος,

German towns, and public banquets ,

of hippophagists are frequent in borne by the many currents of the France, will anemones escape the sea, to settle where it lists, without frying-pan? any fear of parental supervision, and It was hinted just now that the thus lives to a good old age, if no

was but an indifferent one nudges the elbow of Atropos, parent. Having given birth to her and causes that grim lady suddenly offspring, she spends no anxious to cut the thread.+ The anemone hours over the episodes of infancy. has little more than beauty to recom- When I say She, I might as well say mend it; the indications of intelli- He, or It, for no distinction of sex gence being of by no means a power- exists; and probably it is to this ful order. What then? Is beauty cause that the parental indifference nothing? Is it not the subtle charm may be traced ; how can maternal which draws us from the side of tenderness and ceaseless vigilance be the enlightened Miss Crosser to that expected, when the maternal indiviof the lovely though“quite unintellec- dual is as yet undeveloped ? The tual" Caroline, whose conversation, Actiniæ are viviparous. Indeed I indeed, is not of a novel or brilliant suspect they are only viviparous, and kind; whereas Miss Crosser has read not at all oviparous. Rymer Jones

anemone

* The day this was written I could not rest till I had dredged a favourite pond, and brought home a supply of Naïds, with which, on the following morning, I tested Siebold's statement. First I placed a Naïs filiformis in a glass cell with a Hydra viridis; but although its wriggling constantly brought it into contact with the tentacles, it was never grasped. I then placed a Naïs in the phial containing many hydræ; it was instantly caught by one, and held for some time till it struggled itself free. Not only was it apparently unhurt by this contact, but to-day it is as lively as it was three days ago, just before the experiment. With two other Naïds the same result was observed. This completes the overthrow of the current opinion respecting the hydra's paralysing power.

+ The age to which an Actinia may live has not yet been definitely ascertained; but Mr Tugwell communicates in a note that Professor Fleming at Edinburgh has one in his possession, which was taken at North Berwick in 1828; so that, at the very least, it must be twenty-eight years old, that period having been passed in confinement.

VOL LXXXI.--NO, CCCCXCV,

[ocr errors]

seems to hesitate on the point, add- mark of species. Thus, to select ing, “ but it is asserted by numerous a striking example, Mr Gosse makes authorities that the young are not two distinct species of the orangeunfrequently born alive." I not only disked and orange-tentacled anemoassert this, but ask whether any nes, naming them Venusta and one has ever seen the contrary. It Aurora; but as if to prove the indifstartled me, however, when, on open- ference of all such characteristics, I ing an anemone, I for the first time brought with me from Tenby an saw a young one drop out, and im- orange-disked—and only one-which, mediately expand its tentacles; and before it had been home a fortnight, some days afterwards, as I was carry- I discovered, with great surprise, was ing home a lovely “gem,” I saw first changed into an orange-tentacledone, then two, three, four, seven young disc and tentacles being of a rich ones issue from its mouth, fix them- orange hue, the only traces of white selves at the bottom of the vase, and remaining just at the tips. If there make themselves at home ; they were had been any other specimen in the of various sizes, and in various stages vase I might have doubted ; but of development. Since then, I have having only one in company with repeatedly witnessed this mode of a white daisy, and a smooth anebirth ; and one day, seeing something mone, there was no avoiding the in the inside of the tentacle of a Daisy, conclusion. I snipped the tentacle off, and found The reader was promised “New a young daisy there. Some writers Facts,” and those already furnished imagine that the young issue through will show him how great an accesthe orifices at the tips of the tentacles sion to our knowledge may be antici

a supposition not very, credible. pated from the present direction of The truth is, that at the bottom of so many minds towards these anithe stomach there is a large opening mals ; what is written in the best --not several minute openings as books must be accepted as only we see figured in books-through suggestions of a few observers, to be which the young pass from the controlled by the investigations of general cavity into the water; and succeeding observers. Many probthis appears to me the only exit lems await solution; many stereofor the young. Without absolutely typed assertions must be disproved. denying that the ova are extruded, Let us here consider one or two and their early development carried accepted “facts” which will turn out on out of the parent's body, I have to be " fancies” when rigorously never been able to detect ova, except examined. within the parent. The most curious Perhaps nothing has excited more of all my observations on this point surprise on the part of the public, was the finding in the visceral cavity and nothing has been more unaniof a smooth anemone a young one as mously believed by anatomists, than large as a cherry; and to complete the hypothesis that certain minute the marvel, it was faintly striped with organs found in Polypes, and varigreen, like the well-known“ green- ously styled thread capsules, filiferstriped variety,” although its parent ous capsules, or urticating cells, are was of a dark-brown hue. Could organs of urtication, or stinging. the old one have swallowed an errant The uncritical laxity with which youth by mistake? No. It had this hypothesis has been accepted been many weeks in captivity, where may point a lesson. I do not allude no such errant youths were within to the acceptance of the fact that reach : besides, anemones do not certain capsules containing threads swallow each other ; cannibalism be- are found in Polypes, but to the aclongs to a higher grade of develop- ceptance of the alleged purpose or ment. A propos of this peculiarity of function of these capsules. The colour, I 'may remark on the great things are there, sure enough ; but variations observable in the colour of whether they serve the urticating anemones, and the impropriety of purpose is another matter. Ever making colour the distinguishing since they were first described by

Wagner, Erdl, + Quatrefages, and with which some of them seem to be Siebold, I they have passed without furnished, will at once admit that challenge. They have been detected the hypothesis of the "nettling" or in the whole group of Polypes, iu “urtication” being performed by Jelly-fishes, in the papillæ of Eolids, these threads is an hypothesis so and, according to Vander Hoeven, in obvious, an explanation so natural, Planariæ ; yet, as far as my reading that-it should be doubted. In all extends, not one single experiment complex matters, we should mistrust has been made to prove the function the obvious explanation ; I do not so unanimously admitted, not a single say that we should disregard or reject test has been applied to strengthen it, but mistrust it. When we know, or controvert what was, indeed, very on the one hand, that the jelly-fish plausible, but only plausible, not stings, and when, on the other hand, proven. Accordingly, no sooner did we know that it is furnished with I submit the question to that rigor- numerous cells, in which are coiled ous verification which science impe- threads, to be seen darting out when riously requires, than it became clear pressed, the idea of connecting the to me that my illustrious predecessors stinging with these threads is inevi-Wagner, Erdi, Siebold, Quatre- table : but this is not enough for fages, Ehrenberg, Agassiz, and Owen science ; it is only a preparatory --men whom the most presumptuous guess, which proves nothing ; it may would be slow to contradict, had ad- be right, it may be wrong. I believe mitted the point without proof, be- it is altogether wrong. We have cause it wore so plausible an air. already seen how erroneous was the Let me hope the reader will accuse supposition that Polypes paralysed me of no immodesty in thus contro- their victims with a touch ; that verting men so eminent; he will see poison was secreted by their tentacles; that whereas they have only hypo- yet for this supposition there was at thesis on their side, I have the ac- least the evidence of partial observacumulated and overwhelming weight tion, whereas, for the supposition we of experimental evidence.

have now to consider, there is absoWhat are these “ capsules,” or lutely no evidence at all. "urticating cells?” The uninstructed On a survey of the places where reader may be told that the Polypes these “ urticating cells” are present, are supposed to urticate, or sting, we stumble upon an unlucky fact, like nettles; and the nettling or- and one in itself enough to excite gans, or urticating cells, are sup- suspicion. They are present in a few posed to be minute suboval micro- jelly-fish-which urticate; in actiniä scopic capsules, quite transparent, which urticate ; and in all polypes containing within them threads ---which, if they do not urticate, are coiled up, which, on pressure, dart popularly supposed to do so, and at out to many times the length of any rate possess some peculiar power the capsule, into which they never of adhesion. In all these cases return. This thread Agassiz likens organ and function may be said to a lasso thrown by the polype to to go together. But the cells are secure its prey. I will not enter here also present in the majority of into minute details of structure, jelly-fish, which do not urticate; which would only confuse the reader, in Eolids — which do not urticate; who, if curious, will find all that is and in Planariæ which do not known, in the works of Mr Gosse, urticate. Here, then, we have the and the treatises of Owen, Siebold, organ without any corresponding and Rymer Jones. Any one who has function ; urticating cells, but no uronce seen these threads under the tication. The cautious mind of Owen microscope darting out with light- had already warned us that there ning rapidity, especially if he uses a was something not quite satisfactory high power, and detects the hooks in our supposition; some super* WIEGMANN'S Archiv., 1835, ii. p. 215. + MULLER'S Archivo., 1841, p. 423.

I Comp. Anat., i. p. 39 (English Trans.)

« AnteriorContinuar »