the attention of his audience, and his modefty, which confined his views to that purpose, prevented his own felection and revifal of any, except one volume on the prefumptive arguments in favour of the Chriftian religion, which were rather given up to the importunity of his friends, than by himself deftined for publication. It will not then be thought ftrange, if our Author's Difcourfes fhould not bear a critical examen with regard to the minutiae of compofition; more important matters engaged his attention; nor was fame, as a Writer, by any means his aim.' Having given our Readers a fhort sketch of Dr. Duchal's character, we now proceed to his Sermons. In the firft Difcourse of the second volume, he fhews, that Nature, in all its productions, when free from diftemper, and in a proper ftate, is beautiful and lovely; in its animal productions, full of life, full of pleasure and enjoyment: that this is the cafe, in a particular manner, with refpect to mankind when in a right moral state, as the reverse is true, when in a state of depravity. What he principally infifts upon, is the unaccountable folly and abfurdity of those who are in queft of happiness in the ways of fin and unrighteousness, which are a direct contradiction to nature, tend to ruin the excellencies of it, and put it entirely out of its courfe. He fhews, that human nature, when arrayed in the robes of purity and righteousness, when enriched with holy and worthy difpofitions, when full of generous and liberal fenti'ments, of love to God and benevolence to men, is an excellent and lovely form, and worthy its glorious Author. In the fecond Sermon he explains and illuftrates these wordsEphef. iii. 19. That ye might be filled with all the fullness of God. The practical obfervation he makes on this fubject is, that we ought with great care to cultivate devout affections, and apply ourfelves to those exercises by which an intercourse with heaven, and fellowship with God, are maintained. What he advances on this head, is very juft and rational, and deferves the attentive confideration of those who think that the whole of religion confifts in probity of mind, in good difpofitions and behaviour towards our neighbours; that where thefe are found, religious exercises are but little if at all useful; and that a conftant and ferious application to them, is really fuperftitious. He concludes this Sermon with the following words • It has often occurred to my thoughts on this fubject, how much pleasure men take in converfing with each other, where there is hearty love and friendship. Every face is chearful, and the heart is glad; the hours pafs infenfibly; and the entertainment, as it is natural and innocent, fo it is really one of the principal principal in human life. And where is it feen, that men of focial fpirits need incentives to this focial intercourfe? How naturally does a man run into the company and conversation of his dear friends? Now what is this owing to, but love? A man, indeed, goes with reluctance into company which he dislikes. And is not the reverse equally true; that, in fact, a man must diflike that company which he seldom or never affociates with? How obviously applicable this, to the subject of our converse with God! &c.' The neceffity of giving the heart to wifdom; the power the mind has over its affections; and the means by which it may raise and regulate them, is the fubject of the third Sermon. In the fourth, fifth, and fixth, the Doctor difcourfes from those words -Pfalm xxxiii. 15.-He fashioneth their hearts alike-He fhews, in the fourth, that as mankind are formed alike, with refpect to those powers and affections which are effential to human nature; fo there is an infinite diverfity amongft individuals, in many other refpects, and which are of very great importance. From this representation of the state of human nature as we now fee it, he draws feveral pertinent and just observations, which, if duly attended to, will make us pleased with our state as men, thankful to our gracious Creator, fatisfied with his adminiftration, and greatly tend to fecure us from the pains of envy at those who are in fuperior ftations, or have fuperior abilities; and from all difpofition to murmur against him, who, for wife purposes, has appointed all fuch diftinctions. He goes on to obferve, in the fifth Sermon, that the main end of fuch a frame as the human, and the chief good of fuch a creature as man, must be the fame in all the individuals of the fpecics. Whatever is the chief good and the highest end of man, must neceffarily, he fays, have the following characters: it must be what every individual, who fets himself in earnest to pursue after it, may hope to attain; it must be that for the fake of which all things, the enjoyment of which prove inconfiftent with it, are to be given up; it must be that, in which the mind perfectly refts, and is fatisfied; and it must be ftable and durable as the mind itself. In the fixth Sermon, we have a fhort view of that discipline and felf-government, by which we may hope to attain to our highest end, and of the encouragements we have to engage heartily and perfevere in such discipline. [To be concluded in our next.] R. Experimental Experimental Effays on the following Subjects: I. On the Fermentation of alimentary Mixtures. II. On the Nature and Properties of fixed Air. III. On the refpective Power and Manner of acting of the different Kinds of Antifeptics. IV. On the Scurvy; with a Propofal for trying new Methods to prevent or cure the fame at Sea. V. On the diffolvent Power of Quick-lime. Illuftrated with Copper-plates. By David Macbride, Surgeon. 8vo. 5s. Millar. TH HE choice of the various, yet relative, fubjects of these curious Effays, fhews their Author's difpofition to be ufeful to his fpecies, in the important article of health; and his. clear experimental manner of difcuffing them, evinces his confiderable capacity for it. A fenfible preface informs us, their general purpofe is to fhew, that there is another principle in matter befide those which are commonly received; and that it is upon this principle, forming the cement, or bond of union, that the firmness, foundness, and perfect cohefion of bodies chiefly depend.' This is air in a fixed, or non-elaftic, ftate. Mr. Macbride does not affume this theory or difcovery as his own; acknowleging, p. 32, • That Sir Ifaac Newton was well apprized, that the air had a property of paffing from a repellent elastic state, to the oppofite of nonelaftic and ftrongly attractive, and vice verfa; and also well knew the property of elective attraction in the minute particles of matter adding, that it was by pursuing the hint of that great man, that Dr. Hales engaged, near forty years ago, in an enquiry, which enabled him to establish this theory; and which hath fince been illuftrated and confirmed, with regard to a particular clafs of bodies, by the late experiments of Dr. Black on the Magnefia alba.' Our candid Author has alfo profeffed, in the clofe of his preface, that the prefent Eflays were defigned as a fequel to what these two Gentlemen had wrote, and Dr. Pringle had annexed to his Obfervations on the Diseases of the Army, relatively to the fcope and subject of fome of thefe Effays.' The first of them is employed on the Fermentation of alimentary Mixtures: from the beft definition of which term, Mr. Macbride thinks it plain, that the digeftion of our food ought, in particular, to be regarded as a fermentatory procefs. Though this approaches nearer to the ancient theory of digeftion, than that of Boerhaave, and most other modern Physicians, except Hoffman's, which coincides with it, yet we do not observe that our Author is anxious about reviving the opinion of every vifceral humour and fecretion contributing to different modes or 4 degrees degrees of fermentation; for that they fome way conduce to a perfect chylification has never been doubted: but from thofe experiments, which difcover fome degree of fermentation in alimentary Mixtures without the body, digefted in the degree of animal heat, he rationally infers the like procefs to occur in the ftomach and alimentary tube. Indeed, as air is evidently generated, that is, restored from a fixed to an elaftic ftate in all fermentation, we imagine the frequent eructation or emiffion of air from this conduit of the food, will readily produce an affent to fo probable a theory; efpecially when illuftrated by the experiments in this Effay, which have a direct tendency to demonAtrate both this animal fermentation, and the generation of fome principle, during the first stage of the fermentation of animal and vegetable mixtures, which hath a power of correcting pu trefaction... For this purpofe Mr. Macbride made fix different nutritious mixtures, (the firft only of bread and water) the fecond of which, confifting of bread and boiled mutton beat up with a proper quantity of water, he called the fimple fermentative mixture. To four ounces of this he added, in one experiment, two drachms of fresh lemon-juice; in a fecond, one ounce of fpinage; in a third, an ounce of green water-creffes; and in a fourth, two drachms of a very fetid liquor that lay about putrid mutton. All thefe put into different phials, not clofely ftopt, were placed in a moderate degree of heat, on the top of a fand-furnace. A table annexed to this experiment, exhibits a fynoptical view of the various alterations appearing in all thefe mixtures, at the end of fix, of twenty-two, of thirty, of forty, of fifty-four hours, and finally at the end of four days; for which we refer to that Table, page 4, and more particularly to several subsequent pages. -The different ftages of fermentation he diftinguishes into the fweet, four, and putrid, thus characterizing them according to their feveral products upon diftillation. We thould not fomit that two little bits of putrid mutton were fufpended in two of the phials, during their fermentation; and that they -were rendered fweet by the vapour arifing in fermentation; -which vapour agreed with the fubtle-Gas-of-the ancient Ché+mifts in extinguifhing fire; and which pur Author rationally conjectures would alfo fuffocate animals. He fuppofes, neverthedels, this effect on the lungs would not infer any mortal confequence from it in the alimentary duct; this being contrary to continual experience, which makes it probable, that this vapour is the grand preferver from putrefaction; that it attempers acrimony, is a principal agent in nutrition, and, perhaps, contributes fomewhat to animal heat." Mr. Macbride, induced by the fermentation in five of his REV. Oct. 1764. U phials, phials, (the bread and water alone never fermenting for fiftyfour hours, and proving fourish at the end of four days) to conclude, that any vegetable mixed with an animal substance, would alfo ferment, made twenty-one other, but not very different, mixtures, excepting four with human fpittle, all which were placed, fourteen hours after, in a fand-bath. But these experiments were rendered incompleat, by the ignorance of a fervant, who had raised the fire rather to a boiling, than a fermenting heat; whence, upon furveying them fix hours after, Mr. Macbride fuppofed they would never ferment. Yet twelve hours after this, he found feveral of them, tho' quite removed from the fire, in motion: the different degrees of which, and the vifible ftate of all the mixtures, are prefented in a fynoptical table, page 15. A very clear and compendious account of animal digeftion, employs a few of the following pages, with fome practical reflections on the difference of falutary and imperfect digeftion; this Effay clofing with an affertion, that the spirit or vapour which is fet free from the alimentary mixtures, during their fermentation in the firft paffages; which thence enters the compofition of the chyle, and with that fluid is tranfmitted into the blood, there to prevent or correct the putrefactive Diathefis, appears to be chiefly the fixed air of the alimentary fubftances. But as a rational affent to this medical Lemma, or Affumption, requires a knowlege of the properties of this air, when confidered as a conftituent principle of bodies, it very logically refers the Reader to the fecond Effay, On the Nature and Properties of fixed Air. This is really a curious, and no very contracted, difquifition; which commences with obferving, that the excellent Mr. Boyle, who was, in many refpects, well acquainted with the properties, and the generation, of air, was unacquainted with it as the principle of cohefion, which theory, our Author fuppofes Dr. Hales to have eftablished, though Haller alone feems to have given fully and clearly into it; all the other fyftematic Writers in Chemistry or Phyfiology, fuppofing cohesion to depend altogether on the attraction fubfifting between the particles of elementary earth, exclufive of any other principle. To expofe the infufficience of this hypothefis, our Author justly remarks, That if earth were the only caule of cohesion in bodies, there never could be any change in their combination,' very rationally fubjoining, p. 30, It is plain, therefore, that the principle upon which cohesion immediately depends, muft be of a volatile or fugitive nature, not -fixed and indestructible, like earth; otherwife the face of this globe would be covered with dead bodies; for when a stop is put to the life of either animal or vegetable, they become no longer |