opinion, of which however I am not so tenacious as not to yield to more probable reasons.

But I alfo believe, that worms are actually the caufe of fome difeafes. Low and marshy places are not wholefome, and whether we live there, or accidentally fleep by the fide of ftanding waters, we ought not to rely on the ftrength of our conftitution, efpecially in warm weather. The ague, and feveralother difeafes will attack us fooner or later, occafioned, partly by worms generated in the mud, partly by vapours rifing from the water, and which we receive in refpiration. Thefe worms are of fuch extraordinary minutenefs, that a moderate degree of the fun's heat is fufficient to raife them along with the vapour, the parts of which are ftill heavier, than thofe they carry up with them. It is probable, that the diseases which prevail in fuch places, originate from worms, especially as they are moft virulent in fummer, which is the feafon of infects, and as they difappear in autumn, when thefe ceafe to live. But by what means do they thus prey on our conftitution? Do they poifon us by the acrimony of their falts, or do they abridge our days, by devouring the folid parts of our frame? Here I honeftly confefs my ignorance, and without attempting to folve this difficulty, I fhall only infer the caufe from the effects, although the manner in which it operates, is to me, altogether a myftery.

It is likewife undoubtedly dangerous to fwallow certain infects. There is a fort of mildew, which is generally met with, at the bottom of the ftalk of red cabbage. This grofs and fulphureous exhalation is raised by the heat of the fun, and nourishes worms, which are the more to be dreaded, as they are imperceptible to the eye, and, as they often get into the body, along with the food, by the carelefinefs of

thofe

thofe who prepare it. Fruits likewife are always fub ject to the attacks of a fpecies of fly, the eggs and poifon of which they conceal. Our relifh for this kind of food, prevents us from examining it with proper care, and we eat the bad, as well as the good, at the hazard of a dyfentery. I confider this cruel disease, as a neceffary confequence of intemperance, as it prevails only at the time when fruits are most plentiful. Animal food, foiled with the excrement of flies, is likewife a moft pernicious aliment; and, if it is noxious to swallow infects in fubftance, along with our drink, it is unpardonably rafh to ufe fuch food, without having it perfectly purified from all malignity.

I cannot omit to mention, the fatal effects produced by worms upon children, and even upon adult perfons. Thefe worms are generated, either by a fpecies of ichneumon, which depofits them in dif ferent parts of the body, or they enter by means of every thing we eat or drink, and occafion dreadful changes. Either by pricking or gnawing the nerves and fibres, they produce gout, cramp, and in general, whatever is comprehended under the name of fpafmodic contraction. If they are lodged in the fto. mach, they excite fometimes a falfe appetite, fometimes an exceffive loathing; but generally great ficknefs, palpitations, vomiting, cold fweats, faintings, languor and fuffocation. If, on the other hand, they have got to the head, they are the cause of megrim, fyncope and mania; in the throat, fhooting pains and naufea; in the urinary paffages, diabetes; in the ears, continual finging and pain; in the noftrils, extreme itching, and perpetual inclination to fneeze; in fhort, they injure the complexion, by making the face pale and wan, and caufe, in the extremities of the body, alternate heat and cold: thefe accidents, however, are but rare; while other difeafes hardly

ever

ever fail to follow when worms get into the intes tines, for which reafon, it is proper to fay fomething of that matter here. I am ready to confess, that it is difficult to divine the origin of such infects. To fay that they are taken in by inspiration, by food or drink, or by eggs lying in our bowels, either because thefe worms originated there, or for any other reason whatever, is to fay nothing, and each conjecture is attended with more difficulties than proofs. Suppofe we fhould maintain, that these worms were introdu ced with the air, the queftion would ftill remain to be answered, by what means were the feeds of them fpread in the atmosphere? why, amongst mankind in general, fome should be afflicted with worms, while others are free? and lastly, how it is poffible to conceive, that in every perfon, and every where, these infects have always the fame determinate form? Should the entrance of their eggs with our food be maintained, there arifes at once, a very natural objec tion; whence happens it, that there never has been discovered in nature, a worm, fimilar to those that infeft the human body? Befides, is it to be prefumed, that the ftomach is unable to destroy the eggs of thofe infects, when it can diforganize fubftances of the moft difficult digeftion? I do not mean to enter into the fubject, either to investigate the origin of thefe worms, or to develope their effects when produced.

What is not to be refuted, is, their exceffive multiplication in fome perfons, who have voided vaft quantities of them, both by vomit and ftool. I fhall not mention diarrhea, tenefius, ftinking breath, ftarting in fleep, bulimia, atrophy, &c. which are the leaft of the evils which thefe infects fubject us to ; fhall only mention fome difeafes, which either directly or indirectly proceed from them. Some produce melancholy, tremblings, vertigo; others cholic and

afthma,

afthma; many penetrate the vifcera, and threaten the patient with premature death; but it is chiefly in violent fevers, that these guests cause the greatest diforders: As this is an acute difeafe, they throw the patient into convulfions which threaten him with immediate death. How How many direful effects of infects in general might we not adduce, were we to collect what has been related! Uladiflaus duke of Bohemia loft his life by a fly, which, entering in at his throat, came out at the nape of his neck, and caufed an hæmorrhage, which nothing could ftop. Adolphus, count of Juliers, was purfued and killed by infects of the fame kind. Pope Adrian IV. in drinking, fwallowed a fly, which topped in the paffage and fuffocated him.

The venomous qualities of many infects fpread through the air, and on land, have often proved fatal, both to the timid and the curious, to the prudent and to the rafh. It is true, that the cold climates which we inhabit, have this advantage, that infects themselves are not a poifon; It is only their fting, or their bite, which is noxious, and not till they are irritated; for then, their vital fpirits being violently agitated, there is generated a fermentation in their humours, which thereby contract qualities, exceedingly noxious to the bodies into which they are injected. It has been obferved, that these animals are much more fierce in hot than in temperate climates. The reason is evident, the fun acting with much more force in the one than in the other, and attracting more earthy and fulphureous particles, infects acquire humours of a warmer, more pungent, and confequently, of a more malignant quality.

They communicate their venom in various ways; fome, by a fort of exhalation from them, infect the air, and whatever breathes in it: others infinuate it

Gg

into

into the parts they touch: others introduce it by means of their teeth; others get into the body by the mouth. The effects they produce on the human body, differ as much as the means by which they attack it are different. The poifon of fome affects the folids, that of others operates on the chyle; in others it interrupts the circulation of the humours, ftops up the pores, or caufes other diforders, but their venom, though different in different fpecies, has this in common, that it attacks the nervous and fibrous parts, and there causes violent contractions.

The tarantula is an infect remarkable for the effects produced by its venom, on those who are bitten by it. One dances and leaps, another fheds tears; another fleeps inceffantly, another paffes the whole night, without clofing an eye: One perfon will tremble through his whole members, without being able to expectorate or perfpire; another will grow fond of a particular colour, and never find himself fatisfied with looking at it. One perfon will divert himfelf with leaping inceffantly, or in waving a fword; one will delight in looking at a glafs of water, which another cannot endure. One perfon will take pleasure in a lamb decked with green, while his companion will be in an extacy at the fight of a ba fon of water, in which he will repeatedly plunge his arm or his head. Some are fo elevated with pride, that they fpeak only in a high flyle, while others finifh their gambols by whining and lamentation: laftly, fome fall on the ground, and fight with feet and hands, in a frightful manner.

It is common for infects to affociate together in prodigious numbers fo as to compofe immenfe armies, and to make all at once an irruption into a country, whither they bring famine and epidemic difeafes. I repeat it, that I am not of the opinion of thofe who. maintain