acquainted with the means of pre'venting in future fo great a calamity.

"Left the flies may become diffigured in travelling, it may be prudent to fay, that their wings are four; that their antennæ are clubbed, and about one-third of the length of their body, each being compofed of nine joints, namely, two next the head, above which two there is a joint fomewhat longer than the reft, and above this fix more joints, fimilar to the two below; that near the point of the tail of the female there is a black fpeck, outwardly fringed with hair; but which, opening longitudinally, appears to be the end of a cafe, containing a delicate point or fting (about onetwentieth of an inch in length) which on a curfory view appears to be a fimple lanceolated inftrument, with a strong line paffing down the middle, and ferrated at its edges; but, on a clofer infpection, and by agitating it ftrongly with the point of a needle, it feparates into three one-edged inftruments, hanger like as to their general form, with a fpiral line or wrinkle winding from the point to the bafe, making ten or twelve revolutions, which line, paffing over their edges, gives them fome appearance of being ferrated. "By the help of thefe inftruments, I apprehend, the female depofits her eggs in the edge of the turnip-leaf (or fometimes, perhaps, in the nerves or ribs on the under furface of the leaf): thus far I can fay, and I think with a confiderable degree of certainty, that having put fome frefli turnip leaves into a giafs containing feveral of the male and female flies, I perceived (by the means of a fimple magnifier) that one of the females, after examining attentively the edge of the leaf, and finding a part which appeared to me

to have been bitten, unfheathed her inftruments, infinuated them into the edge of the leaf, and having forced them afunder fo as to open a pipe or channel between them, placed her pubes (the fituation of which, from repeated and almost inceffant copulations, I had been able to afcertain precifely, and to the lower part of which thefe inftruments feem to be fixed) to the ori fice, and having remained a few feconds in that posture, deliberately drew out the inftruments (which the tranfparency of the leaf held against a strong light afforded me an oppor tunity of feeing very plainly) and proceeded to fearch for another convenient place for her purpose.

"The caterpillar has twenty feet (fix of its legs being of confiderable length, the other fourteen very fhort) and in its firft ftage is of a jetty black, fmooth as to a privation of hair, but covered with innumerable wrinkles. Having acquired its full fize, it fixes its hinder parts firmly to the leaf of a turnip, or any other fubftance, and breaking its outer coat or flough near the head, crawls out, leaving the skin fixed to the leaf, &c. The under coat, which it now appears in, is of a blueish or lead colour, and the caterpillar is evidently diminished in its fize. In every refpect it is the fame animal as before, and continues to feed on the turnips for fome days longer: it then entirely leaves off eating, and becomes covered with a dewy moisture, which feems to exfude from it in great abundance, and appearing to be of a glutinous nature, retains any loofe or pliant fubftance which happens to come in contact with it, and by this means alone feems to form its chryfalis coat. One I found laid up in the fold of a withered turnip leaf (that which I have the honour of inclof

ing you) was, among fix others, formed by putting common garden mould to them while they were in the exfudatory ftate above defcribed. "From the generic characters of the fly I conclude it to be a tenthredo of Hill; but whether that voluminous author be fufficiently accurate; or whether, from being an almost entire ftranger to natural hiftory, I may, or may not, fufficiently understand my book, I must beg leave to fubmit to your fuperior knowledge of the subject.

"I am endeavouring to extend my

communicate to

obfervations on these infects, and am making fome experiments concerning them, the refult of which I fhould be extremely happy in be ing permitted to you; and it may be proper to add here, that I fhould not have taken the liberty of troubling you prematurely with this letter, had I not luckily met with an opportunity of procuring fome live flies (which are now become very fcarce); and I flatter myself they will come to your hands in a perfect state. "I am, with the greatest respect, &c."

"IN this work all the parts of the human body are defcribed; we have there an opportunity of examining the opinions which have been recommended, or at least advanced, by celebrated authors, who have attributed different ufes to the fame parts. M. de Haller did not always decide between thefe opinions; fometimes he proved that they ought all to be rejected. No thing of importance that had been previously published, efcaped his obfervation, and he almost uniformly added remarks of his own to the intelligence he had obtained from books.

"We fhall not here enter into the immenfe detail of errors which Haller has destroyed in phyfiology; of new facts which he has added; of the ingenious and deep views which he has opened; of the doubts he has cleared up, or of the theories he has perfected or reformed: this would be to copy the whole of his work. We fhall confine ourselves chiefly to thofe fubjects, on which 1783.

he has drawn every thing from his own proper fountain, viz. generation, the formation of the bones, and irritability.

"His numerous experiments which have generation for their object were made on birds. The facility of examining their eggs, at almost all hours of their incubation, prefented him with advantages which he could not have found, had he made his inquiries on any other kind of animals. He traced the formation of the chicken, from the inftant in which the first change in the egg is perceived, and the vital fpeck begins to dilate, to that when the little animal quits the hell in which it has been formed. He faw, if we may ufe the expreffion, the organs fucceffively fpring up before his eyes, acquire life and motion; faw them transformed and perfected; affume the feveral difpofitions allotted to them in the animal; and beheld the arteries and veins unfold themfelves. The veffels of the growing chicken are confufed and form a K

conti.

:

continuity with thofe of the yolk of the egg; and as thefe veffels of the yolk are obfervable in eggs which are unimpregnated, M. de Haller thought himfelf warranted to conclude that the chicken exifted ready formed in the egg, previously to its impregnation. He was equally affured that the foetus is alfo wholly formed in the females of oviparous animals and he regarded this obfervation as a conclufive proof in favour of the fyftem, of the fucceffive developement of germs. He however, perhaps, regarded it as a mere probability; and would not have divested himself of that wif dom which rendered him inacceffible to the fpirit of fyftem, if he had not been inspired with a fecret propentity to this opinion, by reafons of a different kind.

"He apprehended that the produc. tion of an animal, by means purely mechanical, would deftroy one of the proofs of the doctrine of providence. But is it not fufficient for thofe who fearch, in nature, pr proofs of this doctrine, that the phenomena are regulated by certain laws, whatever thefe laws may be ? Is not the cryftallifation of a falt, which constantly affumes the fame form, a phenomenon as admirable as that of the generation of animals? In fhort, the laws which act upon matter, being equally conftant, and the phenomena refulting from them uniformly offering the fame regu. larity, whatever fyftem we employ to explain them, is it not in the wifdom and goodnefs which the whole of thefe phenomena announce, and not in the nature of the powers they produce, that we ought to look for proofs of the existence of a fuperior being?

"It may appear more fingular that M. de Haller thould believe religion or morality to be interested in the

7

opinions of philofophers, concerning the formation of organifed_beings, as he had attacked, in his differtation on monsters, the identical metaphyfical reafonings, which he has fince employed in favour of the developement of germs; and he himself had proved, as we shall prefently relate, that the repofe of a philofopher may be disturbed by thefe trivial charges, which are often too wantonly made and easily admitted.

"In the experiments on offification, M. de Haller traces the progrefs of the growth and folidity of the bones in oviparous animals. He then examines the formation of a callus in the bones of adult animals. He thought he had difcovered, in his experiments, that the bones are, at firit, a jelly of a thin confiftence, but organised and formed of vellels, originally imperceptible to the fight, as being transparent and filled with a colourless liquid. This jelly af terwards affumes a more folid form: the veffels become visible, and it at last offifies, by the blood of the arteries, which pals through, it, de politing in it an earthy matter. According to his opinion, the periofteum contributes nothing to offification, because it has a different or. ganitation from that of the bones; because fome bones have no periofteum, and this membrane is covered by calluffes or offeous pro ductions; and lastly, because in a foetus, the bones at the time they become folid, have no adhesion to the periosteum.

"Thefe opinions of Haller differ from thofe of Duhamel, who explains the formation of the bones by fuppofing a fucceffive offification of the membranes of the periosteum. Indeed fome of M. de Haller's experiments would appear difficult of explanation, if we were to adopt the

theory,

theory of M. Duhamel. Nor is it lefs difficult to account, on Haller's fyftem, for the formation of bony lamina, and especially for the alternate red and white, ftrata, which are obferved in the bones of animals fed, fometimes with their common food, and fometimes with the fame food mixed with madder; fo that these two opinions, both of which are founded on experiments, and advanced by philofophers diftinguished for their averfion to fyftematic ideas, have divided, and ftill continue to divide, phyfiologifts.

"By irritability, M. de Haller means, that property, which certain parts of living bodies poffefs, of contracting when wounded, or even when touched, independently of the will of the animal that is the fubject of the experiment, and without its feeling any pain. A property, which plants feem alfo to partake, and which being diftinct from fenfibility, does not depend on the fame organs. He endeavours to prove, that irritability refides exclufively in the mufcular fibres, and fenfibility in the nerves he demonftrates how, in the different parts of the body, almost all

of which are mixed with mufcles and nerves, the fenfibility, they fhew, depends on the nerves, and their irritability on the muscles; that those parts which are deftitute of mufcles are not irritable, and thofe that are deftitute of nerves are not fenfible; that if the nerves be divided, which unite any part to the brain, the fenfibility of the part will be loft, while its irritability will remain. The nerve, when feparated from the brain, ceases to contract: it only preferves an appearance of motion, because it may ferve as a foreign body to excite irritability in the mufcle to which it belongs. On the contrary, a mufcle, though feparated from the living body, ftill retains figns of irritability; but the power of it is diminifhed, and ceases in a very short time. He cautions against confounding irritability with elasticity, which is a property purely mechanical, and teaches to diftinguish the motions which irritability produces, from thofe merely chemical changes which the application of cauftics induces in all the foft parts of organifed bodies."

"IN the cultivation of pepper, the first circumstance that claims attention, and on which indeed the whole depends, is the choice of proper ground. The experiments hitherto made by Europeans, have not been fufficiently accurate, to determine the particular foil that fuits it beft; but it appears to thrive with nearly equal vigour in all the different kinds, between the two ex

tremes; of fand, which prevails through the low country near the fea coaft; and of the barren, yellow clay, of which is formed the greater part of the rifing grounds, as they approach the hills. The latter indeed, at greater or lefs depth, conftitutes generally the bafis even of the beft foils; but when covered by a coat of mould, not lefs than a foot deep, it is fufficiently

for every purpose of this cultivation. The level ground, along the banks of rivers, if not fo low as to be flooded by the freshes; or even then, if the water does not remain upon it above a day; affords in general the most eligible fpots, both in point of fertility, and the convenience of water carriage for the produce. Declivities, unlefs very gentle, are to be avoided; as the mould, loofened by culture, is liable in fuch fituations, to be swept away by the heavy rains. Even plains, when covered by long grafs only, will not be found to anfwer, without the affiftance of the plough, and of ma nure; their long expofure to the fun, exhaufting the fource of their fertility. How far the produce in general might be increased by the introduction of these improvements in agriculture, I cannot take upon me to fay; but I fear, that from the natural indolence of the people, and their averfeness from the bufinefs of pepper planting, owing in great measure to the fmall returns it yields them, they will never be prevailed upon to take more pains with it than they now do. The planter, therefore, depending more upon the natural quality of the foil, than on any improvement it may receive from his labour, will find none to fuit his purpose better than that covered with old woods; whofe rotting trunks, and falling leaves, enfure to him a degree of fertility, fuperior to any that is likely to be given to other ground, by a people, with whom agriculture is in its infancy. Such fpots are generally chofen by the induftrious among them for their laddangs (paddee, or rice plantations); and though the labour that attends them is confiderable, and it may be prefumed, that their fertility can fercely be fo foon exhaufted, it is very feldom that they feek

from the fame ground, a fecond crop of grain. Allured by the certainty of confiderable produce from a virgin foil, and having land for the most part at will, they renew their labour annually, and defert the plantations of the preceding year. Such deferted plantations, however, are often favourable for pepper gardens; and young woods, of even three or four years growth (balookar), frequently cover ground of this nature, equal to any that is to be met with. Upon the whole, where variety of fituations admits of choice, the preference is to be given to level grounds, moderately elevated, covered with wood, as near as may be to the banks of rivers or rivulets, and the furface of whose foil is a dark mould of proper depth. This is to be cleared as for a laddang; the underwood being first cut down, and left fome days to wither, before the larger trees are felled. When completely dry, and after fome continuance of fair weather, the whole is burned; and if effectually done, little remains to render the fpot as clear as is requifite.

The garden ground is then marked out, in regular fquares of fix feet, or five Malay covits, the intended diftance of the plants of which there are ufually a thousand in each garden. The next business is to plant the chinkareens. Thefe are to serve as props to the pepper vines, (as the Romans planted elms for their grapes), and are cuttings of a tree of that name, put into the ground feveral months before the pepper, that the fhoot may be strong enough to fupport the plant, when it comes to twine round it. Sometimes the chinkareens are chofen fix feet long, and the vine is then planted the fame feafon, or as foon as the former is fuppofed to have taken roof: but the principal objections to this

method