THE NATURAL HISTORY OF ANIMALCULES." 77 "Some animalcules resemble spheres, others are egg-shaped; others again represent fruit of various kinds, eels, serpents, and many of the invertebrated animals, funnels, tops, cylinders, pitchers, wheels, flasks, &c. &c.; all of which are found to possess their own particular habits, and to pursue a course of life best adapted to their particular constructions: thus, for instance, while some move through the water with the greatest imaginable rapidity, darting, leaping, or swimming, others merely creep or glide along, and many are altogether so passive, that it requires long and patient observation to discover any of their movements at all. One description are perceptibly soft, and yield easily to the touch; another are covered with a delicate shell or horn-like coat. Of the latter order there are different degrees of density, as in the voloox, gonuim, &c., where the envelope is comparatively thick, and where, strange to say, the internal substance separates by the mode of propagation into several portions, forming so many distinct young ones, which, at their birth, burst the envelope, and the parent becomes entirely dissipated. In others of this order, the shell is merely a plate covering the body, resembling that of the tortoise; sometimes it includes the body, so as to leave only two small apertures at the extremities, and at others it is broader, and encloses the creature, like that of the oyster or muscle."pp. 11-24. The most minute of these very minute beings form a genus, known by the very appropriate name of monads; and so excessively minute are they, that we are assured many millions of them may be taken up on the point of a pin! One might almost expect from this that Mr. Pritchard was disposed to go the length of the eminent botanist, Mr. Robert Brown, who, a few years ago, maintained (and perhaps still maintains) that "all bodies, organised or unorganised, consist of animated molecules, having a motion peculiar to themselves;" in other words, that every thing in nature is but an aggregate of living atoms, each having a separate and independent existence! But Mr. Pritchard does not go so far as that. Speaking of Mr. Brown, and his animated molecules, he :-"Although says:I have examined them under a magnifying power of 3,000 times linear, nothing like a vital principle, such as is exhibited by the monads, could be recognised❞—thus decidedly confirming the objections taken by Dr. Schultze and others to Mr. Brown's theory (see Mech. Mag., vol. xiv. page 140). The vitality of the monads, however, Mr. Pritchard (as will be seen from the following extract) considers to be not only past all question, but almost past improvement. "This genus of animalcules includes the smallest forms in which a voluntary motion has been observed, even under the most powerful microscopes. This motion, until very recently, appeared to be the only property of life with which they are endowed, but the observations of Dr. Ehrenberg demonstrate an organisation equally perfect with animated beings of much larger dimensions. Their forms in general are simple, spherical or cylindrical masses, devoid of external members or processes; the mouth, which is with difficulty discerned, is a simple orifice, not furnished with ciliæ or hairs (except in one or two species); they are colourless and transparent as the clearest crystal, yet can no internal organisation be seen, excepting that connected with their digestive function, which consists of two or more globular cavities or sacs, probably communicating with each other by a tubular membrane, as in the larger polygastric animalcules, but which in this genus is too minute to be discerned; indeed, the stomachs or sacs themselves are only to be observed when the animalcule is fed with particles of colouring matter; the food on which they mainly exist being as pellucid as themselves; the cavities are invisible. They increase by a spontaneous division of the parent into two or more parts, and those parts or young again divide when they have attained their full size. As subjects of observation, they are principally interesting from their minuteness, being, as they are, the very limit of man's acquaintance with animated nature. Their diameters vary from 1-24,000th of an inch to 1-12,000th, consequently require a very high magnifying power to discern. They are numerous, and generally found congregating at the surface and around the decomposed matter of infusions, either vegetable or animal substances. Muhlenberg enumerates ten species, but Ehrenberg has included fifteen." 78 66 THE NATURAL HISTORY OF ANIMALCULES." We have not the hardihood to contest altogether the vitality of these atoms, against such eminent authorities as Dr. Ehrenberg and Mr. Pritchard-our own experimental knowledge on the subject heing but limited; but we may at least be permitted to question the validity of some of the conclusions which they have here drawn from the facts they observed. They say that the matter they saw was "voluntary motion." Now, admitting that they did observe a motion in these monads, quite distinct from the fluid in which they float-a motion not produced by any change of temperature in, or mechanical motion of, the fluid, which is the utmost, the evidence before us calls upon us to concede--it assuredly does not follow that there was any thing voluntary" in such motion. To assume that, is to take a wide stride beyond what the facts warrant. How, again, is their organisation proved to be “equally perfect with animated beings of much larger dimensions"? It is confessed that no internal organisation can be seen, even with the most powerful microscopes, excepting "two or more globular cavities or sacs." But the globular cavities, we are told, are the "digestive organs the animalcule. And how is this proved? Because colouring matter finds its way into them. But may not the colouring matter find its way out of them as well, without undergoing the slightest alteration? The entrance of colouring matter into some portions of an atom, and not into others, only establishes the simple fact, that there are certain cavities in it; but what the use of these cavities may be, is necessarily all matter of conjec ture. "of The perusal of what follows may even suggest a doubt whether the existence of the cavities in question is as satisfactorily established as Dr. Ehrenberg and Mr. Pritchard imagine. "Monas termo-the End Monad. This animalculæ, as its name implies, is a mere point, even when viewed under considerable magnifying powers; indeed, it is so very minute, that its existence cannot be discovered in the best instruments with a less amplification than 160,000 times (or 400 linear); and when higher powers are used (viz. 800 to 1200 times). it requires considerable address in the management of the light in order to exhibit it. The best illu mination is obtained by condensed lamp seen. light, with proper stops to limit the quantity, for they are so delicate and transparent, that if much light be admitted they cannot be In the aplanatic engiscope, with a power of 800 linear, Dr. Ehrenberg, by feeding them on very finely divided colouring matter, has been able to discern from two to six spots in them, which, by analogy with the larger infusoria, are stomachs, or digestive cavities. It may also be presumed that they possess, like the larger animalcules, but one orifice or mouth for the reception of food, and that they do not imbibe nourishment by cuticular absorption, as hitherto supposed; and it may be observed, that the coloured points occupy the hinder parts. In the drawing (fig. 1) is represented a group of these animalcules, magnified 800 diameters, or 640,000 times in surface: in some of them are shown the dots, as seen when they are fed on indigo; in their natural condition they are merely colourless globules. They differ in size from 1-24,000th to 1-9600th of an inch in diameter; the largest hitherto observed was found at Koliwan; in general, they do not exceed 1-18,000th in diameter. They are often so abundant on the surface of infusions that many millions in a single drop may be taken up on the head of a feeding pin. In the solar achromatic, in the confines of the light, young animalcules have been discerned much smaller than 1-24,000th of an inch, and it is probable that more perfect instruments would exhibit even smaller animated beings; to observe these, however, it is necessary to have finely divided opaque coloured matter in the fluid. It may be doubted whether any reasoning being, whe has seen these minute living atoms, can contemplate them without the most positive conviction, that they are the work of an allwise Creator, and, doubtless, intended by Him for some useful purpose in the economy of nature; for if we consider the almost countless numbers that exist in the small space of only an inch, whither will our imagination lead us, when we think on the myriads that would occupy the back of a single elephant?" Dr. Ehrenberg was certain that he saw the " spots in them;" but, considering that one of these animalcules, 66 even when viewed under considerable magnifying powers," is a mere point, we presume to think that they might have been upon, instead of in them, without the doctor's being very well able to tell how the fact exactly stood. But whether the colouring matter finds its way into the monad, or is deposited upon it, the part which it plays in these investigations furnishes " THE NATURAL HISTORY OF ANIMALCULES." an illustration of the divisibility of matter which is in itself abundantly curious. If we take some of the largest of these animalcules, and suppose them to be arranged in a line of only one inch in length, it will require 9,600 to form it; so that a cubic inch would contain 884,736 millions; an ocular demonstration, it would seem, of the divisibility of animal matter. And if we investigate the thickness of their skins, or the tissue which encloses the coloured particles, it will be found to be less than any substance we are acquainted with in inorganic matter; and will afford, at the same time, a better idea of the minuteness of the particles of vegetable colouring matter than any other method we can devise. Thus, for instance, presuming there are only four particles of colouring matter in each cavity or stomach, and four sacs or cavities in each animalcule, the said cubic inch of animalcules will contain the immense number of 14,155,776 millions of particles; and if the solid matter of the animalcules be supposed to occupy only one half of the space, a solid inch of indigo will contain twice that number of particles." -p. 29. As we ascend the scale of animalcular being from the genus "Monad" to the genus "Vorticella" (" visible to the naked eye") the evidence of organisation becomes gradually more distinct and clear, and is at last too strong to admit of any reasonable doubt. We cannot afford the space requisite to exemplify this by individual instances, but we shall quote a page or two of a general nature, to show the bearings of the evidence, and therewith conclude. "A muscular system being the proper agent of voluntary contraction in the animal kingdom, its existence might fairly be expected in the infusoria; creatures so remarkable for the rapidity and energy with which they propel and translate themselves from one situation to another. In respect to the former, they can only be compared with fishes; in the latter with insects. The mere contractibility of tissue can never surely afford a sufficient explanation of those active voluntary efforts, by which they avoid every obstacle, where myriads of creatures are swiming in a single drop of water, by which also they convey nutriment towards their mouths, and perform the acts of deglutition. * The superior size and diaphonous nature of the vorticella, enable us, under the microscope, to discern several distinct bands of fibres, of a greyish white colour; that these fibres perform the office of muscles is evident, by their contraction and dilata 79 That these filaments and ganglia (alluding to certain appearances distinct from those last noticed) are not muscles, is evident from their form, their mode of insertion, and their not being shortened in the contraction of the animal, but assuming a serpentine form, being apparently passive. That they are not vessels is also evident, because no pulsation or circulating fluid has ever been per. ceived in them: hence, by fair reasoning, we may safely conclude that they form a nervous system; and it is well remarked by Mr. Johnston (Edin. Phil. Journal), that, according to all our ideas of known physiological laws, the existence of active voluntary motion presupposes the necessity of an animating nervous system."―pp. 165, 166. HEATONS' STEAM CARRIAGE. Sir, The advocates for steam travelling on common turnpike - roads, have, for some time past, been anxiously awaiting the debut of Messrs. Heaton, Brothers', new locomotive, which has at length taken place. The sanguine expectations which Messrs. Heatons' previous eminently successful experiments gave rise to, have, however, been disappointed, by the results of more recent trials with the new and more powerful engine. In this engine the weight, wear and tear, and consumption of steam, have proved so much greater than was calculated upon, that Messrs. Heatons' have been compelled to entertain views on the subject differing widely from those with which they started. In the course of a few experimental trips with their new engine, which is a very beautiful machine, Messrs. Heatons have been compelled to doubt the possibility of steam locomotion on common roads, at an average speed of ten miles an hour, the wear and tear of machinery, with other incidental expenses, being so great as to exceed any probable receipts; profitable running, there fore, at this speed-and it is presumed a slower would not be tolerated-they believe to be imprac ticable. The following paragraph appeared in the Birmingham Journal of the 12th instant: "We are authorised, by the committee of Heatons' Steam-carriage Company, to state, that the result of the experiments hitherto made with their engine has not proved satisfactory, and that they will shortly call a meeting of the shareholders, to take into consideration a communication made to the committee by Messrs. Heatons on the subject." After expending upwards of two thousand pounds in endeavouring to effect steam travelling, Messrs. Heatons now retire from the field; their candid and upright conduct throughout this business is highly honourable to them, and forms a striking contrast to the delusions practised elsewhere. I am, sir, yours respectfully, W. BADDELEY. 10, Wilderness row, Goswell street, April 28, 1834. 80 NOTES AND NOTICES. NOTES AND NOTICES. The country is much indebted to Mr. Smith, of Southam, for his exertions to promote the establishment of dispensaries, for the purpose of enabling the labouring classes to defray, from their own resources, the expense of medical treatment. It appears to us that great good has already been effected by these dispensaries, and that much more may be effected by them; but we are not prepared to suggest any legislative measures for their encouragement.-The Report of the Poor Law Commissioners. We have repeatedly recommended these admirable institutions to the attention of our readers, and are glad to learn that they are on the increase. One has been recently established in St. Pancras, which offers to the industrious artisan surgical and medical attendance for the small sum of sixpence per month, and the choice of any one of nine regular practitioners of the highest respectability. Steam Carriages.-On Tuesday last, a single carriage, belonging to the Steam Carriage Company of Scotland, performed the most successful runs that have ever been accomplished on the common roads, having gone six successive trips with passengers between Glasgow and Paisley, and in an average time of 41 minutes; the first trip having been done in 40 minutes, the second in 43, and so on, being a distance, in all, of 46 miles in 42 hours, at a rate of more than 10 miles an hour.. On the previous day, the same carriage had run the distance four times at a similar rate, and on Wednesday it was again done within 40 minutes. The other carriages continue running daily, and the communication between Glasgow and Paisley, by means of these carriages, may now be considered as fully and permanently established-Glasgow Argus. The Athenæum states that the Observatory at Mackrea Castle, Coloony, in the county of Sligo, belonging to Edward Joshua Cooper, Esq., the member for that county, has been enriched with an equatorial refracting telescope, of the extraordinary length of 23 feet 6 inches, the diameter of its object-glass being 13 inches and 3-10:hs. The weight of the tube and its mounting is 3 tons; yet so perfectly steady is this stupendous instrument, that Mr. Cooper has been already enabled to make very satisfactory micrometrical measurements of the most difficult double stars. The polar axis, which is upwards of 7 feet long, is supported on a pyramidal mass of masonry. The tot I cost, exclusive of the object glass, has been less than 500%., and the whole has been completed within the short space of eleven months, by two ingenious Dublin artists, of the names of Sharp and Grubb. The object-glass is by Guinand, and figured by Cauchoix. We are sorry to learn, from the same authority, that Sir James South has not yet been able to make use of the large equatorial telescope which he lately erected at his Observatory on Campden-hill, Kensington, owing to its unsteadiness. tr The failure of chloride of lime to remove certain noxious smells," of which "Rusticus" complains, has no doubt arisen from some impropriety in the method of employing it. He has probably placed it in an open saucer, on or near the floor of the apartment he wished to purify-a very common practice-and because it gave forth its peculiar odour in abundance, he may have imagined that its disinfecting virtue was in full operation. If so, it is no wonder he should have been disappointed. The disinfecting virtue does not reside in the peculiar odour, but in the chlorine gas contained in the chloride; nor does it follow, that where there is an abundance of the former, there must be any appreciable disengagement of the latter. Chlorine is so much heavier than the common atmospheric air, that it diffuses itself through it with difficulty so much so, that it has been calculated thate hloride of lime does not emit, spontaneously, one thousandth part of the gas embodied in it. It may be readily disengaged, however, by pouring a few drops of muriatic acid upon the chloride in the sancer; and if our correspondent will try this, we think he will find that its purifying properties have by no means been overrated. The durability of Mr. Chubb's Detector Locks was lately put to a remarkably severe test in the dock-yard at Portsmouth. One of them having been attached to a steam-engine, so as to be alternately locked and unlocked by the action of the piston, it went through this process no less than 460,000 times, and when examined, was found not in the least injured by the extraordinary friction to which it had been subjected. The Smalls light-house, in St. George's Channel, is erected on iron pillars, 40 feet high, which are bedded in a half sunken rock, but so great is the danger of the situation that, in case of accidents, the lantern itself is said to be placed in a boat! The revenue derived from it is divided between two female individuals (one of them a lady), and amounts, after payment of all expenses, to between 8,000, and 9,000l. per annum. It is surely high time that this, and all light-houses similarly circumstanced, should be brought under the control of Government. The ascent of Holborn-hill might, in the opinion of an intelligent correspondent (C.), be rendered much less difficult and dangerous, if it were paved partly with granite and partly with wooden blocks, after the manner lately described in this Journal as practised in St. Petersburgh. We think so, too; and hope the suggestion may meet with attention from those who have the power to carry it into effect. The total number of light-houses in Great Britain and Ireland is 178. In England there are 98, of which 34 are under the direction of the Trinityhouse, 54 belong to corporate bodies, and 10 are held by female individuals. In Scotland there are 42, of which 26 are managed by the Northern Light Commissioners, and 5 are in female hands. Ireland has 38, all under the management of the Ballast Board of Dublin. Boiler Plates vary from a quarter to threequarters of an inch in thickness. J. P. will be safe with the quarter of an inch size, if the metal is of the best quality. The thickness has nothing to do with the size of the boiler, but is the same for all sizes under the same pressure. Dr. Church's Steam-Carriage was started for the -first time, on Friday evening, from the manufactory. It proceeded at a very rapid rate (say from 15 to 20 miles an hour), with about forty passengers upon it, for a considerable distance, when, in turning short about upon the road, the hind part struck the footpath, and broke a small appendage to one of the valves. It was then deemed advisable not to work the machinery further, for fear of accident, but to attach the ropes and hanl it back by the workmen.-Birmingham Gazette. Communications received from Mr. J. R. White -Mr. Holmes-G. D.-Mr. Saunders-Clio-Mr. Blackett. The Supplement to our last Volume, containing Title, Table of Contents, Index, &c., with a Portrait, on Steel, of William Symington, the Inventor of Steam Navigation, is now ready, price 6d.; also Vol. XX., complete, in boards, price 8s. LONDON: Published by M. SALMON, at the Mechanics' Magazine Office, No. 6, Peterborough Court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. RICH, 12, Red Lion square. Sold by G. G. BENNIS, 55, Rue Neuve, Saint Augustin, Paris. M. SALMON, Printer, Fleet-street. |