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beetle. So far from the last animal possessing an imperfect sight, according to the vulgar proverb, it is furnished with above 3,000 eyes, each of them possessing a distinct lens and optick nerve. The same essay contains some remarks on the brain of the gnat, and the circulation of the blood in the crab. The next object that is described, is, the proturberance which is occasionally found on the leaf of the willow; and which is the work of an insect that lays its eggs on the surface of the leaf, and, at the same time, seems to penetrate into its substance, and act on it in such a way as to produce this excresence, which serves as a receptacle for the future animal. A section on the loadstone follows, which is less interesting than some other parts of the work, because our knowledge of the properties of this substance is very much extended since Leeuwenhoek wrote. We cannot assent to an opinion advanced by the translator, that any analogy subsists between the loadstone and the polypus, merely because every fragment of a magnet becomes itself a perfect magnet, in the same way as the parts of a divided polypus each form a perfect animal. The next essay, on the brain of the turkey, the sheep, and the sparrow, is particularly to be noticed, as containing many observations on the size of the particles of the blood. The hypothesis which the author formed of a descending series of
globules, which was afterward taken .
up and embellished by Boerhave and the other humoral pathologists, seems to be one of the few instances in which M. Leeuwenhoek suffered his fancy to warp his accuracy of observation. He informs us in his essay, that he saw a fluid issue from the vessels of the brain, “ composed of very minute globules, 36 of which would not be cquai in size to a globule of the human blood;’ and that, “ besides
these small globules, there were some larger ones, of which,” he says, “I judged that six would be equal in size to one globule of human blood.” Some curious remarks
follow on the minute fleshy fibres.
The author was able, by means of his glasses, to detect them when of so small a size, that a million occu
pied only the size of a square inch.
He particularly examined the mus
cles of a flea's foot; and, by compar
ing them with those of the larger
animals, he inferred that the ulti
mate fibres of all were of the samesize.
“I continued my observations,” he says, “by examining the flesh taken out of the feet of a flea, and I saw no difference between the formation and figure of the fibres, taken out of the breast and the feet, and I saw more than twelve of such fibres in the foot of a flea, joining to each other, and also many smaller fibres, in which I could not distinguish the folds or wrinkles; these last I took to be exceeding small blood vessels and nerves. “I also took the flesh out of the feet of small flies, and saw the fleshy fibres in them to be formed in the same manner as beforementioned.
“The fibres which compose the substance of a whale, I also found to be each enclosed in a membrane, and to be composed of still smaller filaments; and with regard to the size of these fishy fibres, each single fibre was no larger than in the smaller fish; and, indeed, I have seen the fibres in some codfish, eight times the size of those in a whale.
“I also examined the component fibres in the flesh of a mouse, a calf and a hog, and found their formation to be the same as before described, namely, each surrounded with a particular membrane, and composed of smaller filaments: the fibres
in the flesh of all these animals was nearly
of the size I have before laid down, so that I may say, the fleshy fibres composing the body of an ox are not, singly taken, larger than those which go to the substance of a mouse, though, as I have computed, the one animal is thirty thousand times the size. of the other.” From some interesting remarks on the external membrane of the human skin, it appears to consist of a. continuous layer of proper scales,
so extremely minute that 200 of them “may be covered by a com1mon grain of sand;” they are disposed with great regularity, and are of a pentagonal figure. It would seem that the skin has no proper pores, except such as exist in the interstices of these scales. The author thinks that their number is the same at all ages, and that therefore, as the body increases in size, each individual scale must grow proportionably. We have next some observations on gouty and urinary concretions, and on the nature of gunpowder; subjects on which the author’s knowledge was necessarily very deficient; and we afterward come to a train of microscopical experiments on the louse, which, were it not for the disgust excited by the object, we should rank among the most attractive parts of the volume. We shall only notice one fact, which the writer seems to have discovered, that the sensation of itching, produced by these animals, is not caused by their bite, but by a sting which the male protrudes from the extremity of its body. M. Leeuwenhoek’s next investigations relate to some of the most minute animals that are perceptible to the naked eye, viz. the mite, the different kinds of insects which injure fruit-trees, and the animalcules that are found in the sediment of water. To the subsequent paper, which gives an account of the circuhation of the blood in the tail of the eel, the translator subjoins a description of the microscopes which were employed, taken from the writings of Mr. Baker. In the next essay, on frogs, and on the manner in which they are produced from tadpoles, we have a number of additional observations on the globules of the blood, especially respecting their shape and size:
“In my several observations on the circulation of the blood in fishes, I have not been able clearly to satisfy myself with
Vol. v. 2 U.
position in which they appeared to the
eye, for, while in circulation, they tumbled one over another, sometimes presenting one part and sometimes another to the view; and I also thought that it might be owing to the straightness of the vessels, in which the particles of blood, being of a yielding nature, might, by the compression, lose their spherical figure.
“In order to satisfy myself in some degree on this head, I cut off pieces from the tails of several small, flat fish, such as plaice and flounders, in order to view the blood when drawn out of the vessels, and the rather, because I could not persuade myself, that the natural shape of the particles of blood in fishes was an oval; forasmuch, as a spherical seemed to me to be the more perfect form. For I was of opimion, that the particles of blood in fishes were composed of six globules, in like manner with the blood in man, and in terrestrial animals: and I several times saw the particles of fishes’ blood, the original texture of which was broken, and in which I could distinctly see four or five, and in some few of them six component particles. I, however, thought it worthy of note, that many of these particles of blood appeared to me of an oval shape, some few others roundish, and others of a perfect spherical figure.
“ In order farther to prosecute my inquiries on this subject, I took the blood of a salmon not quite dead, which was received into a glass tube, about the size of a small writing pen: this blood, after a short time, became coagulated; but having restored it in part to its fluidity, I put it into a smaller glass tube, in which I viewed it, holding it so, that the particles of blood might be kept in motion continually, by which means many of the particles appeared before my sight with a flat and oval shape; in others, the sides of which were turned towards me, I could scarcely perceive any sensible thickness; and in short, others, where their sides were not exactly turned towards me, appeared somewhat broader in proportion to their size; but I could not discover one particle of blood of a perfect spherical shape.”
We have quoted this description
at length, because it is a subject which has given rise to much controversy, and the passage must impress the reader with a favourable opinion of the author's candour. Apparently, he could scarcely be deceived respecting the shape of the globules, although we do not assent to his theory of their composition. We now come to some remarks on phosphorus, and on the sting of the gnat; experiments on insensible perspiration; observations on the common fly, and on the eggs of the shrimp; essay on the salts contained in pepper, tea, and cantharides; on the embryo plant discoverable in seeds and buds; and on the structure of the nerves. The observations on the nerves are very curious; and had they obtained more general attention, they might, perhaps, have prevented the appearance of some of those idle hypotheses which have been formed respecting the origin of the sensations. The author speaks of the nerves as being “composed of very minute vessels of an incredible thinness, which, running by the sides of each other, constitute a nerve.” As to the size of them, the vessels are described as being so small, that “ some hundreds of them go to the composition of a nerve no larger than the hair of a man’s beard; and although (says the writer) these cavities, or the orifices of these vessels, are so wonderfully minute, I have seen living creatures in the waters, which could have moved and swam about in them with freedom.” We are informed that the author, at the time when he made these minute observations, was not less than eighty five years of age. A paper succeeds on the quantity of air contained in water and other fluids; and afterward a description of an ingenious contrivance for illustrating the effect which the earth’s motion about its axis must -have on the atmosphere. It is supposed that the centrifugal force will throw off the clouds from the cen* * * * * * *
tre, and thus support them at some distance from the earth’s surface. In some remarks on the circulation of the blood, the principal object is to show that the circuit must be complete in different times, according to the distance of the parts from the heart. By comparing together the observations which he has made on various subjects, the author concludes that the blood circulates through the tail of the eel thirteen times in an hour, while in the upper parts of the body it will circulate ninety six times. Provided that the blood in the human body moves at the same rate as in the eel, it will
pass through the lower extremities
only between two and three times in an hour, through the upper extremities above four times; and through the head eight times: but, in an hour, as much blood will pass through the heart as is equal to fourteen times the quantity contained in the whole body. The proportions of these numbers may probably be correct, but we think that the whole estimate is considerably too low. With some remarks on the nature of lime, on wood that has been worm-eaten, and on the eyes of fish, the volume concludes. The estimate of Leeuwenhoek's merits as a naturalist must be considerably raised in the minds of those who peruse these volumes; and who, though they may have frequently heard him quoted, or have occasionally examined some parts of his works, had not before so fully conceived the extent of his labours. His writings have certainly been too much neglected, and therefore we cannot but express our obligation to Mr. Hoole for putting them in so commodious a form, in a translation which seems to be well executed; and we must not omit to render a due tribute of applause to the excellence of the engravings. The notes, which are occasionally added, do not, in our opinion, increase the value of the work: but they are
SPIRIT OF THE MAGAZINES.
BIOGRAPHY OF VISCOUNT BOLING BROKE.
Bolingbroke, on being appointed minister, immediately repaired to Paris, to solicit succours of all kinds from Louis XIV. His embassy, however, did not prove completely successful; for, although something was obtained, yet the aged monarch was hastening fast towards the conclusion of his career, and had become not only indisposed to a new war with France, but almost incapable of business. A little money, some arms, and one or two vessels fitted out by the merchants, constituted all the supplies he could obtain in the name of “king James.” The regency of the duke of Orleans, was still less favourable to the affairs of the exiles; and the keen and discerning eye of Bolingbroke had already anticipated the disasters which soon after occurred to his party, both in England and Scotland. Bolingbroke did not accompany the prince in his ill-concerted expedition to Scotland, having remained at Paris for the purpose of obtaining succours from Spain; but on the return of this personage, he was dismissed from a service which was not very pleasing to him; “ for he conceived but a low opinion both of the talents and character of his royal highness. For example, it was never possible to obtain a categorical answer on the article of religion, supposing he ever ascended the throne of Great Britain, and although that was a principal article with the English, this prince, there
fore, was at bottom no better than a bigot, as his faith was founded on the fear of the devil and of hell, and not on the love of virtue, the horrour of vice, the knowledge of the reciprocal duties of men living in society, and, in short, on the respect due to the supreme Being. It is but justice to Bolingbroke to add, that the duke of Berwick, who was an eyewitness of his conduct, allows that he acted with great honour and propriety; and remarks, with great force and efficacy, on the jealousies of the earl of Mar and the duke of Ormond, who envied his superiour talents and credit. “One must be entirely destitute of good sense,” says this celebrated general, “ not to know that king James committed a most enormous fault, in dismissing the sole Englisman capable of managing his affairs, and that too, at a time when he stood in the greatest need of his services.” From this moment, Bolingbroke most sincerely abjured not only the services, but also the cause of the pretender: “I then took a resolution,” says he, “to make my peace with king George, and to employ all the experience, which I had unfortunately acquired out of my native country, for the purpose of undeceiving my friends, and thus contributing to the reestablishment of union and tranquillity.” Soon after this, some explanations
earl of Oxford, who had been committed so long to the tower, was brought before the house of peers, and acquitted, in consequence of a dispute with the commons. Notwithstanding this, his colleague still remained in a foreign land. The urbanity and gayety of the French nation appeared to be very suitable to his disposition; he was accustomed to deem himself “ the least unfortunate of exiles;” He possessed a sufficiency of money to live in a handsome style; and his company was eagerly solicited by all the men of talents in France. In 1717, he formed an acquaintance with the marchioness de Villette whose maiden name was Maria Claire Deschamps de Marcilly, and who had been married to the marquis Villette Mursay, a relation of madame de Maintenon. She was then a widow with several children, had been educated at St. Cyr, and lived in the faubourg Saint Germain. This lady was about fifty-two years of age, possessed a very considerable fortune, and at the same time had a number of law-suits. “Without being handsome, she knew how to please. She possessed wit, and might be said to have conversed with great effect, provided she had spoken but a little less.” Bolingbroke soon felt himself in love with her; and as she was pleased with him, a close and intimate friendship immediately commenced, which was, however, frequently interrupted and embittered by his jealousy. , Imagining one day, at dinner, that she had a liking for Mr. Macdonald, first esquire to the pretender, and a
very handsome man, he overturned the table in a fury, and broke all the glasses. The abbé Alari, who was a witness to this scene, was accustomed to observe, in addition; “ that in 1715, Madame de Villette had intrusted him to carry to the count de Boulainvilliers, who piqued himself on drawing horo-copes, the date of her birth, and a variety of other particulars, for his opinion.” The answer was, “that the lady was affected by a great number of passions; that she would experience one stronger than all the rest at the age of fifty-two, and at length die in a foreign country.” All this prophecy,” adds the editor, “ was afterwards fully realized; and yet no reliance whatsoever ought to be placed on the skill of the fortuneteller, who was completely deceived in respect to the predictions made by him in respect to himself. At length, after a variety of lapses, lord Bolingbroke concentrated his passion for the whole sex in Madame de Villette alone, and his own lady, who had turned devotee, having died in November, 1718, the publick conduct of the two lovers from that moment became less embarrassing. He first accompanied this lady to her estate at Marcilly, near Nogent sur Seine, and afterwards conducted her to the waters of Aix-la-Chapelle, where it was generally believed that they were married in May, 1720. It was also asserted, that Madame de Villette, at the same time, abjured the catholick religion: but the abbé Alari, and all those intimate in the family, were fully persuaded that no abjuration had taken place, and that no marriage had ever been completed. It was convenient, however, to keep up appearances, although they never avowed their union until the month of July, 1722. The viscount loved the country, and Marcilly would have proved a most agreeable residence; yet in 1719, he purchased the little estate of la Source, near Orleans, and con