The Zoologist/4th series, vol 2 (1898)/Issue 684/Editorial Gleanings
EDITORIAL GLEANINGS.
"Mimicry," of which we hear so much, and know so little; a theory well substantiated by facts, but too often scandalized by loose suggestions and more or less ingenious guesses; a doctrine somewhat neglected by zoologists, and far too much in the hands of the evolutionary camp followers,—still demands, in very many details, verification by experiment. Mr. Frank Finn, the Deputy-Superintendent of the Indian Museum, Calcutta, has, since 1894, undertaken this work in the province in which he now resides, and has published the results of thorough and well designed experiments in a series of papers (i.-iv.) in the 'Journal' of the Asiatic Society of Bengal. The details of these experiments, carefully studied, will serve to qualify much current misconception; at the same time the results are not negative, but, on the whole, confirmative. In butterflies the Danainæ are generally considered as highly protected. With birds, Mr. Finn tells us:—"The common Babblers (Crateropus canorus) ate the Danaine butterflies readily enough in the absence of others, but when offered a choice showed their dislike of these 'protected' forms by avoiding them. This avoidance was much more marked when the birds were at liberty, though even so a few of the objectionable butterflies were eaten." "In several cases I saw the birds apparently deceived by mimicking butterflies. The common Babbler was deceived by Nepheronia hippia, and Liothrix by Hypolimnas misippus. The latter bird saw through the disguise of the mimetic Papilio polites, which, however, was sufficient to deceive the Bhimraj and King Crow. I doubt if any bird was impressed by the mimetic appearance of the female Elymnias undularis. But this is not a first-rate imitation, and a mimic is put to a very severe test when offered to a bird in a cage or aviary."
As, a result of the whole series of experiments, the following conclusions are reached by Mr. Finn:—"1. That there is a general appetite for butterflies among insectivorous birds, even though they are rarely seen when wild to attack them.2. That many, probably most, species dislike, if not intensely, at any rate in comparison with other butterflies, the 'warningly-coloured' Danainæ, Acræa violæ, Delias eucharis, and Papilio aristolochiæ; of these the last being the most distasteful, and the Danainæ the least so.3. That the mimics of these are at any rate relatively palatable, and that the mimicry is commonly effectual under natural conditions.4. That each bird has to separately acquire its experience, and well remembers what it has learned." And that, therefore, on the whole, the theories of Bates and Wallace are supported by the facts detailed.
The following extracts are from an excellent summary in the 'Globe':—
"In his introduction to a Report just issued by the Scotch Fishery Board relating to investigations on the life-history of Salmon, Dr. D. Noel Paton (Superintendent of the Laboratory) states that the curious life-history of the Salmon has always been a subject of the deepest interest, not only to the zoologist and physiologist, but also to the sportsman and the fisherman. In spite of the most careful study by scientific investigators, the migrations of the Salmon, and the various changes in condition which it undergoes, are even now far from being fully understood, and the careless observations and foolish traditions of keepers, fishermen, and ghillies have only served to involve the matter in a deeper cloud of mystery.
"Questions to be answered.—What force urges the fish to leave its rich feeding-ground in the sea? Is it necessary that it should enter fresh water in order to perform the act of reproduction? Does it require or procure any food during its sojourn in the river, and, if not, how is it able to maintain life, and to construct its rapidly-growing genital organs? In the female the growth of these is enormous. In April or May the ovaries constitute only about 1.2 per cent, of the weight of the fish.—in November they are no less than 23.3 per cent. In a fish of 30 lbs. in the spring they weigh about 120 grms.—in November they weigh over 2000 grms. The increase in the testes in the male is not so marked, but is sufficiently striking. In April or May these organs are about 0.15 per cent, of the weight of the fish, while in November they are 3.3 per cent. From what are these structures formed? As they grow, the muscle, as is well known, undergoes marked and characteristic changes. Not only does it diminish in amount as the season advances, so that the fish which have been some time in the river become smaller in the shoulder and back, but it loses its rich, fatty character, while it becomes paler in colour. Are these -changes in the muscle connected with the growth of the ovaries and testes? And if so, in what manner and to what extent? On the other hand, in fighting its way up rapids and over falls an enormous amount of muscular work is accomplished by the Salmon. Whence is the energy for this work obtained? Are the changes in the muscle connected with the performance of this work, and if so, to what extent are these changes connected with the muscular work, and to what extent with the growth of the genitalia? Lastly, the question arises, to what extent do these changes in the muscle modify the value of the flesh as a food stuff?
"Facts established.—In the investigation of some of these questions, most excellent work has already been done, not only in Holland and Germany upon the Salmon in the Rhine by Dr. Hoek and Professor Miescher Ruesch, but also by Mr. Archer, the Inspector of Salmon Fisheries for Scotland, in conjunction with Mr. Grey and Mr. Tosh. The careful series of observations embodied in the annual reports are well worth careful study by the zoologist and the Salmon fisher. They should help to dispel the absurd traditions which cling around the history of the Salmon, and to pave the way for the complete solution of many of the problems we have enumerated. The present investigation is a continuation and amplification of these researches, and would have been impossible without these previous laborious studies. Briefly stated, these investigations of the Fishery Board have established the following facts:—That some Salmon spawn every year, though there is strong evidence that all do not do so. That the genitalia of fish coming from the sea develop steadily from April on to the spawning time, and that the genitalia of Salmon in the earlier summer months develop more rapidly than those of Grilse. That the proportion of the weight of the fish is constant for all sizes of Salmon. That Salmon continue to feed while in the sea until September. This is shown, firstly, by the presence of food in the stomach of a certain proportion of the fish captured, and, secondly, by the fact that the fish leaving the sea are somewhat heavier—from 2 to 3 per cent.—in August and September than they are in the earlier months, whereas if they had entirely stopped feeding they should have been lighter. If Salmon do feed in the sea, it is perhaps curious that food should be found in so small a percentage of those captured at the mouths of rivers. But it must be remembered that the estuary of the river is not the natural feeding-ground of the Salmon, and it is probably only by chance that food is still in the stomach of fish captured there."
"Mr. Consul Hearn, in his latest report on the trade of Bordeaux to the Foreign Office, makes some striking observations as to the folly of the destruction of birds. He points out that the appearance of the Cochylis, a most destructive insect, is contemporary with the destruction of small birds in the vineyards. No sooner does the 'chasse' open than every man and boy is seen with a gun, stalking and 'potting' every small bird he can get near enough to. The consequence is that there is literally no bird life among the vines, and consequently insect life now reigns supreme. On one property alone, from July 20th to Sept. 10th, 5000 days' labour of women and children was alone employed in looking for and destroying the eggs and larvae of this insect. 'But if only birds were allowed free action they would,' the Consul says, 'assuredly, gladly accomplish this work, and the women and children might be employed in more remunerative labour. In the streets of Bordeaux, during the autumn and winter, Thrashes and Starlings are offered for sale by thousands, and yet these birds' live exclusively on insects.' It is not surprising to learn that a Bill is shortly to be introduced into the Chamber for the protection of birds 'useful to agriculture.'"—Westminster Gazette.
It is evident that the crusade against murderous millinery needs to be renewed, and that in quarters where one would have supposed it to be least necessary. A lady communicates to the 'Christian World' the startling fact that at the May meetings she has noticed Ospreys everywhere, even on the platform. At one important ladies' missionary meeting, both the lady who presided and a missionary who described the cruelties of Indian life wore Ospreys. She supposes they have been told that their plumes were imitation, but adds that in nineteen cases out of twenty they were real.
In 'Popular Science News' (New York), Mr. John Mortimer Murphy has contributed a most interesting article on the Alligator. We read that M the Alligator is rapidly disappearing in the settled regions of Florida, and becoming scarcer every day even in such remote regions as the Everglades, owing to the war of extermination waged against it by hide-hunters, taxidermists, and dealers in curiosities. These pursue it night and day, year in and year out. The little fingerlings just out of the nest are in great demand, as they are worth from two to three dollars per hundred in the local markets. The 'curio' dealers who purchase them often resell them at a dollar each to northern visitors, or else they kill and stuff them into card-plates, cigar-holders, or whatever else their fancy suggests, and dispose of them at good prices. The young are frequently lured from their lurking-places by a poor imitation of the grunts of their mother, and men expert in mimicking her may capture a large number in a day, as they respond promptly to the calls, and pour out of cavities in hot haste to see the caller. The most expert 'gator callers' I ever knew were swamp rangers, both white and black, who were born and bred within a short distance of an Alligator swamp, and therefore knew every intonation of the saurian 's voice. These men could make a matron charge wildly at them across a broad stream by imitating the frightened cries of her young, or lure a decrepit old bull by mimicking the grunts of the female. They could, in fact, delude both old and young, and often earned good sums by their art."
Enormous flocks of Starlings have this year taken possession of and made their ne9ts in the huge chimneys of Buckingham Palace, and these in great numbers forage for their food in the private grounds of the palace.—Daily Chronicle, May 9 th.
The announcement of the untimely death of Dr. C. Herbert Hurst, formerly on the staff of the Zoological Department of the Owens College, will be received with general regret. We take the following obituary notice from the columns of 'Nature':—"Dr. Hurst was an alumnus of the Manchester Grammar School, and studied biology under Professor Huxley with conspicuous success. After some experience as a resident science master in a boys' school he entered the Owens College as a student in 1881, and in January, 1883, was appointed to the post of Demonstrator and Assistant Lecturer in Zoology under the late Professor Milnes Marshall. For eleven years he filled this office with conspicuous diligence and success, and not only earned the grateful recollection of several generations of students of the College, but also laid under obligation a much wider circle of zoologists by his share in the production of the 'Text-book of Practical Zoology,' which has made the names of Marshall and Hurst familiar in every biological laboratory, not only in this country but in the world. In 1889 he took advantage of a prolonged leave of absence, granted by the College authorities, to pursue his studies at the University of Leipzig, where he carried out a valuable investigation into the life-history of the Gnat (Culex), for which he was awarded the degree of Ph.D. Latterly he had undertaken what he termed ' a systematic criticism of biological theory,' in the course of which he published discussions on 'The Nature of Heredity,' 'Evolution and Heredity,' 'The Recapitulation Theory,' and other kindred topics. In these essays certain modern views were subjected to trenchant and unsparing criticism, for Dr. Hurst was a keen controversial writer, and never hesitated to express himself clearly and forcibly, even at the risk of obloquy and unpopularity. His last writings were, 'The Structure and Habits of Archæopteryx,' and 'A New Theory of Hearing.' In 1895 Dr. Hurst left the Owens College to fill a similar position in the Royal College of Science, Dublin. His premature death deprives Zoology of a zealous and upright worker who was most esteemed by those who knew him best."
To compass the death of an Elephant is no light matter. Sportsmen by the head-shot now no longer pursue the slow, costly, and painful method described by Gordon Cumming. Recently, an Elephant contained in "Barnum and Bailey's Show," which had been visiting Liverpool, exhibited traits which, in safety to the public, demanded its destruction. Strangulation was the method selected as being the most merciful, and the following particulars are extracted from 'Nature':—"At the appointed hour those specially invited, among whom were several veterinary surgeons, Dr. Forbes, Director of the Liverpool Museum (to whom the body was generously to be handed over as a gift from Mr. Bailey to the museum), Dr. Roberts and Mr. Burnham, of the Society for the Prevention of Cruelty to Animals, found the Elephant standing quietly in one of the large tents, in line with some twenty to thirty others. A new Manilla rope was loosely wound three times around its neck, and its legs, fully stridden, were securely chained each to a post firmly driven into the ground alongside each limb. The animal was intentionally not isolated from its fellows, as it was feared that if separated by itself it would become restive and illtempered. The rope surrounding the beast's neck had one end secured to three strong pillars in the ground, some distance away and slightly in advance of the fore feet; and the other, which terminated in a loop, was hooked to a double series of pulleys, to the tackle of which ninety men were attached. When all was ready, the slack was gently, quietly, and without any apparent annoyance to the Elephant, which kept on eating hay, taken in till the coils round its neck were just taut. The word was then given, 'Walk away with the rope.' Amid perfect silence the welldisciplined company walked away with it without the least effort. So noiselessly and easily did everything work that, unless with foreknowledge of what was going to take place, one might have been present without realizing what the march of these men meant. The Elephant gave no sign of discomfort, either by trunk or tail; its fellows standing close by looked on in pachydermatous unconcern; and at the end of exactly thirty seconds it slowly collapsed, and lay down as if of its own accord. There was absolutely no struggle, and no motion, violent or otherwise, in any part of the body, nor the slightest indication of pain. In a few seconds more there was no response to the touch of its eyelashes or other parts of the eye, and this condition remained for a few minutes; but through, perhaps, the leakage into the chest of a small quantity of air, some slight sensitiveness returned to the eye, seen on touching its inner angle, though not the cornea. On slightly tightening up the rope, the chest gave one or two short throbs, and after six and a half minutes all movements ceased, and sensation was entirely lost; while at the end of thirteen minutes from the order to ' walk away,' the eye had become rigid and dim."
As we go to press we have heard with the greatest regret of the death of Mr. Osbert Salvin, the well-known ornithologist and entomologist. An obituary notice will appear in our next issue.