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Natural History.

ZOOLOGY.

RESEARCHES IN EMBRYOLOGY.

DR. MARTIN BARRY has presented to the Royal Society the Second Series of his Researches. The author having in the First Series* investigated the formation of the Mammiferous Ovum, describes in this second series its incipient development. The knowledge at present supposed to be possessed of the early stages in the development of that ovum, consists chiefly of inferences from observations made on the ovum of the bird. It appearing, therefore, highly desirable to obtain a series of observations in continuous succession on the earliest stages of development of the ovum of the mammal, Dr. Barry has purposely confined his attention to a single species, namely, the rabbit, of which he examined more than 100 individual animals. Besides ova met with in the ovary, apparently impregnated, and destined to be discharged from that organ, he has seen upwards of 300 ova in the fallopian tube and uterus; very few of the latter exceeding half a line in their diameter. The results of these investigations have compelled the author to dissent from some of the leading doctrines of Embryology, which at present prevail, as respects not only the class mammalia, but the animal kingdom at large. Philosophical Magazine, No. 92; which see for the corroborative facts.

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ARTIFICIAL INCUBATION.

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AN exhibition has been opened in Pall Mall, bearing the classical denomination of " The Eccaleobion;" the object of which is the Hatching of Chickens by Heat. By such means, in this exhibition-room alone, it is possible to bring into existence, through winter as well as summer, a hundred birds a-day, or upwards of 40,000 in a year. exhibition is, however, chiefly to be prized as the means for investigating the process of nature in advancing an organic substance to vitality. Eggs may be broken daily, as they proceed in their development, and examined by the aid of the microscope; thus exposing to view the actual commencement of life, and the gradual formation of those members which life is to animate. In an experiment, about the fourth or fifth day, the first trace of a distinguishable organ appears, where an opaque and cloudy spot had hitherto been witnessed. is the heart of the bird. By placing the egg conveniently on cotton, in a common wine-glass, with water at 98, and keeping it to that temperature, it is easy to continue the observation. for eight or ten hours. From the heart, fine filaments spread over the surrounding

This

*A notice of the First Series will be found in the Year-Book of Facts, 1839, p. 158.

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surface. Anon, circulation begins to appear in them; and soon we are able to distinguish the auricles, veins, and arteries, in full playin one, yellowish atoms flowing rapidly like sand in an hour-glass; and in the other, assuming a redder colour. Again, a dark speck is observed; and, even before this single broken egg is exhausted, it is ascertained to be the future eye of the chicken. Day after day, similar microscopic inspection will show how the work advances-fibres, brain, intestines, muscles, bones, beak, feathers, are all formed in this wonderful sphere-the yolk, the white, and the shell, contributing their various functions, till about the fourteenth or fifteenth day, when the birds are so far matured in the shells as to be hatched by keeping them moderately warm; the warmth of the human body, or 98° of Fahrenheit, being the standard.

From a description of the machine, which is capable of containing above 2,000 eggs at a time, are detached the following relative facts. Greater heat is required to bring forward, say 1,000 fresh eggs, than to mature 1,000 during the last week of incubation. Thus, a heat is, after a while, generated by the eggs themselves; or a lesser heat is required at the end than at the beginning. Birds in a healthy condition require no assistance to effect their escape from the shell; which operation they perform by making a circular fracture of the shell with their bill, and bursting its integuments by strong muscular exertion. In cases of weakness in the bird, or defective hatching, assistance may be given; but such birds generally die in a few days, or, perhaps, hours. Darkness is also considered favourable to the process. Few eggs, excepting those of rare or foreign birds, are worth the trial of hatching, if more than a month old. Very hot weather destroys vitality in a few days. An egg having been frozen is, of course, also worthless. This machine does not, as is frequently the case with eggs sat upon by the parent bird, ever addle them. This evil is occasioned by the alternation of heat and cold, arising from the hen's unsteady sitting. The warmth imparted by the Eccaleobion is uniform and continued. A flush of fresh cool air passing over them each day, for a short time, is considered beneficial. The chicken, at the time it breaks the shell, is heavier than the whole egg was at first.-Literary Gazette; abridged.

DIGESTIVE ORGANS OF INFUSORIA.

M. EHRENBERG considers the separation and isolation of the stomachic vessels of Infusoria as surprising only to those who have not observed earth-worms cut to pieces. Mere pieces, he remarks, let them be ever so minute, contract at each extremity in such a manner that but very little of the contained juices escapes, and a similar effect is produced by the contraction of the isolated stomachs of the Infusoria. One fact, undoubtedly, is more forcible than all arguments; and M. Dujardin only regrets that that of a venicle containing fragments of Oscillatoria has not presented itself several times to the observer; for, with respect to the alleged stomachs without contained aliments, even when they appear slightly coloured, the false comparison with the pieces of earth-worms will not suffice to prove that the globules are not part of the gelatinous substance of the Infusoria; since M. Dujardin has frequently seen these globules

coloured, either from their having a tinge of their own, or that this effect was the result of an optical illusion, or of a phenomenon of accidental colours.-Annales des Sciences, Natur.; An. Nat. Hist.

MEADOW LEATHER.

AN interesting vegetable production, having a deceptive resemblance to white dressed glove-leather, has lately been found on a meadow above the wire-factory at Schwartzenberg, in the Erzgebirge. A green slimy substance grew on the surface of the stagnant waters in the meadow; which, the water being slowly let off, deposited itself on the grass, dried; became quite colourless, and might then be removed in large pieces. The outside of this natural production resembles soft, dressed glove-leather, or fine paper; is shining, smooth to the touch, and of the toughness of common printing (unsized) paper. On the inner side, which was in contact with the water, it has a lively green colour, and we can still distinguish green leaves, which have formed the leather-like pellicle. Dr. Ehrenberg has submitted this meadow-leather to a microscopic examination, and has found it to consist most distinctly of Conferva capillaris, Conferva punctalis, and Oscillatoria limosa, forming together a compact felt, bleached by the sun on the upper surface, and including some fallen tree leaves and some blades of grass. Among these Conferva lie scattered a number of siliceous infusoria, chiefly Fragilarice and Meridion vernale, including sixteen different sorts, belonging to six genera; besides three sorts of infusoria, with membranous shields, and dried specimens of Anguillula fluviatilis.—Philosophical Magazine.

POLARIZATION OF LIGHT BY LIVING ANIMALS.

MR. J. F. GODDARD having observed that the scarf-skin of the human subject, sections of human teeth, the finger nails, bones of fishes, &c., possessed the polarizing property, he was led to examine some living objects with his Polariscope, when he discovered that, among many others, the larvæ and pupa of a tipulidan gnat (the Corethra plumicornis), possessed the same property, and that in a very eminent degree. Its existence in the different substances above enumerated is exceedingly important; but that it should also exist in living animals is infinitely more so, and opens a new field altogether, disclosing characters that lead to an intimate knowledge of their anatomy, and which cannot possibly be discovered by any other

means.

This creature is found in large clear ponds, generally in great abundance when met with; but this is by no means common. Having constructed a water-trough, made with two slips of glass about 1.25 inch wide and two inches long, with very narrow slips of thin glass cemented with Canada balsam between them, at the bottom and sides, thus having it open at one end with about 0.050 of an inch space between in the middle, Mr. Goddard filled it with clear water, in which he placed some of the larvæ; and such was the extraordinary transparency of the creature, as to display, in a most beautiful manner, the whole of its internal structure and organization; and which, when

viewed in polarized light, present the most splendid appearances. Thus, when they place themselves with their head and tail both in the plane of primitive polarization, or in a plane at right angles to it, they have no action upon the light transmitted through them; but when in a plane inclined 450 to the plane of polarization, the light is depolarized, their whole bodies becoming illuminated in the most brilliant manner, varying in intensity according to their size, and the nature of the different parts and substances; the peculiar interlacing of the muscles marking out regular divisions, which, as the creature changes its position with regard to the plane of polarization, exhibit all the varied hues and brilliant tints that have rendered this important branch of physical optics exceedingly interesting.

And, while thus viewing them, if we place behind a thin plate of sulphate of lime or mica, the change and play of colours, as the creature moves, are greatly increased, and are surpassingly beautiful.

These phenomena in the larvæ of the Corethru plumicornis are seen, if possible, in a more splendid manner, in the spawn of many large fishes; but more particularly, in the young fishes themselves, many of which, in their early state, are equally transparent, particularly if of marine production.-Philosophical Magazine.

MEXICAN MUMMIES.

A MILLION of mummies, it is stated, have lately been discovered in the environs of Durango, in Mexico. With them were found fragments of finely worked elastic tissues, (probably our modern Indiarubber cloth,) and necklaces of a marine shell found at Zacatecas, on the Pacific, where the Columbus of the forefathers of the Indians probably, landed from Hindostan, or from the Malay or Chinese coast, or from their islands in the Indian Ocean.- Philadelphia Presbyterian; Silliman's Journal.

WEIGHT OF BLOOD IN THE HUMAN BODY.

THE following account of the quantity of blood in the human frame at the different stages of existence, is given by Dr. Valentin in the Bulletin Général de Thérapeutique Médicale:- In the male subject, the blood at birth weighs 0·73 of a kilogramme (the kilogramme is 2lb.); at one year, 2.29; at two years, 275; at three, 3.03; at four, 3.46 at five, 3.83; at six, 4.14; at seven, 4.62; at eight, 5·10; at nine, 5.52; at ten, 5·99; at eleven, 6·38; at twelve, 7.11; at thirteen, 8.10; at fourteen, 9-28; at fifteen, 10.64; at sixteen, 12.24; at seventeen, 13-16; at eighteen, 14.04; at nineteen, 14:52; at twenty, 14.90; at twenty-five, 15.66; at thirty, 15.80; at forty, 15.78; at fifty, 1547; at sixty, 15.02; at seventy, 14.45; at eighty, 14.04.-In females, it is as follows: At birth, kilogramme, 0.59; at one year, 1.88; at two, 2:31; at three, 2.52; at four, 2.87; at five, 3.14; at six, 3.39; at seven, 3.74; at eight, 4-02; at nine, 4.55; at ten, 4.90; at eleven, 5.32; at twelve, 6·19; at thirteen, 7·03; at fourteen, 7·72; at fifteen, 8.37; at sixteen, 9.01; at seventeen, 9-95; at eighteen, 10-77; at twenty, 11.04; at twenty-five, 11-17; at thirty, 11.18; at forty, 11-49; at fifty, 11.85; at sixty, 11.50; at seventy, 10.89; at eighty, 10:45.

NEW MODE OF RESUSCITATION FROM DROWNING.

AT the annual meeting of the Bristol Humane Society, the Society's silver medal was presented to Dr. Fairbrother, of Clifton, for his exertions in recovering a boy who had been under the water in the floating harbour about half an hour, another quarter of an hour having elapsed before the doctor could operate on the body. The most remarkable feature in this case is the new mode by which Dr. Fairbrother succeeded in his laudable object: namely, by closing the boy's mouth with his finger, sucking off the foul air from his lungs through the nostrils, and promoting respiration by pressing on the abdominal muscles on the side. The usual method is to inflate the lungs; but it is very seldom that persons are recovered by this method if they have been longer than a few minutes under the water.

LONGEVITY.

(From the First Annual Report of the Registrar-General of England, in 1837-8.)

AMONG the diversities which especially demand attention, and by which there is least danger of being led to false conclusions, are those which relate to Longevity, showing the varying proportions of deaths in old age in different portions of the kingdom. From a few instances of Longevity no inference can be safely drawn; but the fact that, of the deaths in any district, a comparatively large portion is above the age of seventy, is a strong presumption in favour of the healthiness of that district. These proportions are found to vary greatly. In the whole of England and Wales, out of 1000 deaths, 145 have been at the age of seventy and upwards; while in the North Riding and northern part of the West Riding of Yorkshire, and in Durham, excluding the mining districts, the proportion has been as high as 210. In Northumberland, excluding the mining district, Cumberland, Westmoreland, and the north of Lancashire, the proportion has been 198; in Norfolk and Suffolk, 196, in Devonshire, 192, and in Cornwall, 188. In contrast with this evidence of the large proportion of persons who attain to old age in these more thinly-peopled portions of the kingdom, we find results extremely different where the population is densely congregated. In the metropolis and its suburbs the proportion who have died at seventy and upwards has been only 104: and even this proportion is favourable, when compared with that of other large towns; the proportion in Birmingham being 81, in Leeds, 79, and in Liverpool and Manchester only about 63. A comparison of the mining parts of Staffordshire and Shropshire, and of Northumberland and Durham, with the rural districts surrounding each, exhibits great differences in this respect, the former averaging 109, and the latter 76. A very marked diversity also appears in the proportion of deaths of infants in different parts of the country. In the mining parts of Staffordshire and Shropshire, in Leeds and its suburbs, and in the counties of Cambridge and Huntingdon, and the lowest parts of Lincolnshire, the deaths of infants under one year have been more than 270 out of 1000 deaths at all ages; while in the northern counties of England, in Wiltshire, Dorset and Devon, in Herefordshire, and Monmouthshire,

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