"Places Nature has appeared obfequious, as it "were, to his Rules: and that he has, by his diligent and careful Researches, penetrated into "the true State of Nature, and perceived the real "Courses and Periods of Difeafes, as they readily "flow from the Mechanifm of the human Body "difturbed in fuch and fuch Ways.

Bet farther to illuftrate the Hippocratical Doctrine of Fevers and their Crifes, and to fhew the Uniformity of Nature in different Countries, Dr. Martine has prefented us with divers Phenomena of intermittent Fevers, viz. tertian and quartan Agues, as they have appeared in various Climes and Ages; by which a very unexpected Concert of the Diseases of Greece, Italy, and Spain, is perceived with those of England.

And for a further Confirmation of this Point, he takes alfo a particular Survey of fome other Fevers, those especially of the efflorefcent Kind, which run their several Stadia or Courfes in determined Periods of Time, much the fame in all Countries, where they have been carefully obferved, and accurately defcribed. The most remarkable, and what most frequently occurs of this Kind, is the Small-Pox: And on this accordingly our Author infifts more largely. He takes notice of its dubious Origin, the Date of that being uncertain; of the firft Subjects and Defcribers of it, the Arabians; of the earliest Notices we have of it, and the Country in which we then meet with it, viz. Egypt, about the Middle of the feventh Century. He then briefly treats of the different Species of this Malady; affigning their Periods, and fpecifying their Symptoms and Iffues.

But not only the natural Difeafes, as our Author has fhewn, have their fettled Periods; even those that are procured by Art obferve Rules very much like the others. This he proves to be true of the Small

He

Small-Pox when procured by Inoculation. gives fome Account of this Method of raising the Diftemper in China and South Wales. He tells us where it was long in ufe before its Introduction into Europe; and defcribes its Phænomena and Periods, as they have been noted in Turky, America, England, Scotland, and Flanders.

Other Diseases in which thefe Crifes are vifible, are the Measles and the Scarlet Fever: In the first especially, as Dr. Martine evinces by a brief History of that Malady, as it appeared at London and elsewhere in different Years.

The other Kinds of efflorefcent Fevers do not (he fays) seem to have fuch orderly and regular Stadia as thofe of a variolous and morbillous Nature; and therefore their Periods cannot fo well be fettled, tho' fome of them may perhaps have been seen by the Greeks, as well as by the Physicians of the fucceeding Ages. The Febris miliaris, treated of by Sir David Hamilton, is of the efflorefcent Kind, and is a very diftinct Species, accompanied by peculiar Symptoms, and performing its Course in regular Periods of Time, if it always really comes up to his Defcription. But this is a Point not yet thoroughly fettled, and our Author leaves it to be determined by future Obfervations. In the mean time he does not doubt but there may be miliary Fevers differing very much from that of Sir David, and which may be found to have their respective Crifes.

Petechial or flecky Fevers have fubfifted time out of mind, and are endemial in fome Places, as in Cyprus and the neighbouring Ifles: Thefe Dr. Martine thinks may come under the Character of periodical, tho' their Stadia are not fo obvious and certain as thofe of others. Nor is it any Wonder, he fays, if fuch Fevers obferve no regular Course: "Where-ever fuch Flecks appear, they argue a

C 4

"more

more than ordinary Diffolution of the Blood, "6 are often contagious, commonly dangerous, and "reckoned in fome measure peftilential, or tending that way.

Indeed, as he adds, we could not expect great Uniformity in thefe terrible Vifitations upon Mankind, which go under the Name of the Plague, and peftilential Difeafes, or are any ways akin to them. And yet even these seem to conftitute Speciefes by themselves, or to be fpecifically different one from another, as well as from all other Difeafes. "Some

Plagues feize only on the vegetable Kingdom, "fome on the brutal Creation, and that sometimes "on one Kind of Animals, fometimes on others, "fometimes on Man and Beaft, and frequently "Man feems to be the only Sufferer. Yea those "of a given Conftitution are tolerably uniform in "their Symptoms; and, what is very furprifing, " befide other Characters of Regularity, do com"monly kill in determinate Spaces of Time." This our Author confirms by a Number of Obfervations, collected partly from Hiftory, and partly from experienced medical Writers.

By all which is evinced, beyond any reafonable Question, "the Regularity of epidemic Dif eafes, not only thofe of a more benign Kind, "but even those of a peftilential Nature; and that they of a given Sort and Conftitution obferve "much the fame Times and Periods in different

Perfons and Places. A remarkable Inftance of "the Uniformity of human Nature even in a de"praved and corrupt State.

The Doctrine of Crifes and critical Days, our Author fays, was the Child of Experience, and nurfed up in daily Obfervation. — And thus far, taking it as a Piece of Natural History, that is, as a Collection of Facts, or of the Phænomena of Difeases, it makes a very elegant and ufeful Part of

medical

medical Knowledge. But the Mind of Man, as Dr. Martine notes, is always eagerly bent on penetrating into the Causes of Things, and feeing the various Springs, Laws, and Inftruments of Action. A moft delightful Science, when free from all falfe Suppofitions and false Reasoning.

"Hippocrates was fenfible of the Infufficiency of "the human Faculties to explain the Nature of one Species of Facts, without the Affiftance, and, as

it were, borrowed Light of a great many others. "And therefore, though he had, with incredible "Pains, made and collected very many Observations concerning the Crifes and Events of many Distempers; yet, confcious of a great deal of the neceffary Data being yet wanting, he very "flightly touched upon the Explanation of the Va"riety of the Periods of Difeafes, and only regi

ftering the Facts he had obferved, left the Philo"fophy of them to the Inquiries and Industry of e future Ages.

Our Author complains, that "the plain and naked "History of Crises, as laid down by Hippocrates, was "not allowed to fubfift long in its original Simplicity. "Those who knew vaftly lefs of Nature than he, urg'd "by the abovefaid Curiofity, would however go be66 yond him, and explain the Reafon and Connexion "of critical Days in a philofophical Way. This was "undertaken by the metaphyfical Phyficians, who "making ufe of fome unintelligible Expreffions of "Numbers, injudicioufly borrowed from the Py"thagorean Philofophy, thought they had in a few "Words given a Reafon for the extraordinary "Harmony that was obferved in the Duration of "Diseases. But Galen and others have fufficiently "fhewn how improperly thofe Numbers of Unity, Binary, &c. are applied in this Matter. Yet Galen himself, as the Doctor goes on, could not leave this Matter untouched. The Caufe of critical

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Days

Days was chiefly, according to him, the conjunct Operations of the Sun and Moon; the Period of which last he was forced grofly to mifreprefent, to make it agree with the received Phænomena of Crifes. Many have implicitely followed his Notion upon this Head; but at the fame time he has laid himself open to be confuted by all those who had the Courage and Freedom of Mind to diffent from him.

Our Author, who fays this, on the other hand commends the Modefty and Referve of Avicenna, who indeed is at the Pains to give us a fhort Sketch of the common Galenical Accounts of this Matter, but fignifies his own Diftruft of them; and looks upon the Crifes and critical Days, as fo many Obfervations, the Truth of which we know by Experience, but the Reason of which was not fo evident or ready at hand, and belonged rather to the Philofopher than to the Phyfician.

Succeeding Writers generally seem to ascribe the whole to Nature; contenting themselves with telling us, that Nature being burthened with fuch and fuch Loads of noxious Humours, is at length, by their ripening, irritated to expell them out of the Body.

This, as Dr. Martine fays, is just falling back again into the indefinite Observations of Hoppocrates; and he feems to think we are unable to do any better. "We fee, as he notes, the Incubation of "Eggs accomplished juft in determined Spaces; "every Species of Fowls having its own peculiar "appointed Time, wherein the young Chickens "are brought to Light. We fee the fame thing "holding in the Pregnancy of viviparous Creatures, "who all have their fettled Times of Geftation, "there being feldom any great Anomalies in this "refpect. The like may be faid of the Increase

and adult State, and Decay and Death of Ani"mals: all which have their determined Spaces of "Duration,