Page images

the attention of his audience, and his modesty, which confined his views to that purpose, prevented his own selection and revisal of any, except one volume on the presumptive arguments in favour of the Christian religion, which were rather given up to the importunity of his friends, than by himself destined for publication. It will not then be thought strange, if our Author's Discourses thould not bear a critical examen with regard to the minutiæ of composition ; more important matters engaged his attention ; nor was fame, as a Writer, by any means his aim.'

Having given our Readers a short sketch of Dr. Duchal's character, we now proceed to his Sermons. In the first Dircourse of the second volume, he shews, that Nature, in all its productions, when free from distemper, and in a proper state, is beautiful and lovely; in its animal productions, full of life, full of pleasure and enjoyment: that this is the case, in a particular manner, with respect to mankind when in a right moral state, as the reverse is true, when in a state of depravity. What he principally insists upon, is the unaccountable folly and absurdity of those who are in quest 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 course. He shews, that human nature, when arrayed in the robes of purity and righteousness, when enriched with holy and worthy dispositions, 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 second Sermon he explains and illustrates these words Ephes. iii. 19. That ye might be filled with all the fullnefs of God. The practical observation he makes on this subject is, that we ought with great care to cultivate devout affections, and apply ourselves to those exercises by which an intercourse with heaven, and fellowship with God, are maintained. What he advances on this head, is very just and rational, and deserves the attentive consideration of those who think that the whole of religion consists in probity of mind, in good dispositions and behaviour towards our neighbours; that where these are found, religious exercises are but little if at all useful; and that a constant and serious application to them, is really superstitious. He concludes this Sermon with the following words

• It has often occurred to my thoughts on this subject, how much pleasure men take in converfing with cach other, where there is hearty love and friendship. Every face is chearful, and the heart is glad; the hours pass insensibly; and the entertainment, as it is natural and innocent, so it is really one of the

principal principal in human life. And where is it feen, that men of social spirits need incentives to this social intercourse? 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 dilike that company which he seldom or never associates with ? How obviously applicable this, to the subject of our converse with God! &c.'

The necessity of giving the heart to wisdom; the power the mind has over its affections; and the means by which it may raise and regulate them, is the subject of the third Sermon. In the fourth, fifth, and fixth, the Doctor discourses from those words -Pfalm xxxiii. 15.--He fashioneth their hearts alike-He shews, in the fourth, that as mankind are formed alike, with respect to those powers and affections which are effential to human nature; so there is an infinite diverfity amongst individuals, in many other respects, and which are of very great importance. From this representation of the fate of human nature as we now see it, he draws several pertinent and just obfervations, which, if duly attended to, will make us pleased with our state as men, thankful to our gracious Creator, satisfied with his administration, and greatly tend to secure us from the pains of envy at those who are in superior stations, or have superior abilities; and from all disposition to murmur against him, who, for wise purposes, has appointed all such distinctions.

He goes on to observe, in the fifth Sermon, that the main end of such a frame as the human, and the chief good of such a creature as man, must be the same in all the individuals of the specics. Whatever is the chief good and the highest end of man, muft necessarily, he says, 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 sake of which all things, the enjoyment of which prove inconsistent with it, are to be given up; it must be that, in which the mind perfectly rests, and is satisfied; and it must be stable and durable as the mind itself.

In the fixth Sermon, we have a short view of that discipline and self-government, by which we may hope to attain to our higheft end, and of the encouragements we have to engage heartily and persevere in such discipline. [To be concluded in our next.]



[ocr errors]


Experimental Esays on the following Subjects: 1. On the Fermenta

tion of alimentary Mixtures. II. On the Nature and Properties of fixed Air. III. On the respective Power and Manner of a£ting of the different kinds of Antiseptics., IV. On the Scurvy; with a Proposal for trying new Methods to prevent or cure the same at Sea. V. On the diffolvent Power of Quick-lime. Illuftrated with Copper-plates. By David Macbride, Surgeon. 8vo. 55. Millar.

HE choice of the various, yet relative, subjects of these

curious Essays, Thews their Author's disposition to be use ful to his species, in the important article of health ; and his. clear experimental manner of discusing them, evinces his considerable capacity for it.

A sensible preface informs us, their general purpose 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-elastic, ftate. Mr. Macbride does not assume this theory or discovery as his own; acknowleging, p. 32, • That Sir Isaac Newton was well apprized, that the air had a property of passing from a repellent elastic ftaté, to the oppofite of nonelastic and strongly attraclive, and vice verfâ; 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 since been illustrated and confirmed, with regard to a particular class of bodies, by the late experiments of Dr. Black on the Magnesia alba.' Our candid Author has also professed, in the clofe of his preface, that the present Elays were designed as a sequel to what these two Gentlemen had wrote, and Dr. Pringle had annexed to his Observations on the Diseases of the Army, relatively to the scope and subject of some of these Effays.

The first of them is employed on the Fermentation of alimentary Mixtures : from the best definition of which term, Mr. Macbride thinks it plain, that the digeftion of our food ought, in particular, to be regarded as a fermentatory process. Though this approaches nearer to the ancient theory of digestion, 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 visceral humour and secretion contributing to different modes or 4

degrees degrees of ferimentation ; for that they some way conduce to a perfect chylification has never been doubted: but from those experiments, which discover fome degree of fermentation in alimentary Mixtures without the body, digested in the degree of animal heat, he rationally infers the like process to occur in the ftomach and alimentary tube. Indeed, as air is evidently generated, that is, restored from a fixed to an elastic state in alí fermentation, we imagine the frequent eructation or emiffion of air from this conduit of the food, will readily produce an aflent to so probable a theory; especially when illuftrated by the expe: riments in this Effay, which have a direct tendency to demonItrate both this animal fermentation, and the generation of some principle, during the first stage of the fermentation of animal and vegetable mixtures, which hath a power of correcting putrefaction. * For this purpose Mr. Macbride made' fix different nutritious mixtures, (the first only of bread and water) the second of which, consisting of bread and boiled mutton beat up with a proper quan: tity of water, he called the simple fermentative mixture. To four Ounces of this he added, in one experiment, two drachms of fresh lemon juice; in a second, one ounce of spinage; 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 these put into different phials, not closely stopt, were placed in a moderate degree of heat, on the top of a fand-furnace. A table annexed to this experiment, exhibits a sýnoptical view of the various alterations appearing in all these 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 stages of fermentation he distinguishes into the - fweet, four, and putoid, thus characterizing them according to their several products, upon distillation. We would not tomit, that two little bits of putrid. mutton were suspended in

two: of the phials, during their fermeritation ; and that they -were rendered sweet by the vapour arising in fermentation ; - which vapoor agreed with the subile-Gas-ef-the ancient Ché* mifts in extinguishing fire; and which' pur Author rationally conjectuses would allo suffocate animals.--He fuppofes; neverthés lelso this effe&t on the lungs would not infer any mortal confequence from it in the alimentary duct; 'this being contrary to continual experience, which makes it probables that this vapour * is the grand preserver 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.O&. 176.4.


phiali, phials, (the bread and water alone nevér fermenting for fiftyfour hours, and proving sourilh at the end of four days) to conclude, that any vegetable mixed with an animal substance, would also ferment, made twenty-one other, but not very different, mixtures, excepting four with human spittle, all which were placed, fourteen hours after, in a fand-bath. But these experiments were rendered incompleat, by the ignorance of a servant, who had raised the fire rather to a boiling, than a fermenting heat; whence, upon surveying them fix hours after, Mr. Macbride supposed they would never ferment. Yet twelve hours after this, he found several of them, tho' quite removed from the fire, in motion : the different degrees of which, and the visible state of all the mixtures, are presented in a synoptical table, page 15.

A very clear and compendious account of animal digestion, employs a few of the following pages, with some practical reflestions on the difference of falutary and imperfect digeftion; this Effay closing with an assertion, that the spirit or vapour which is set free from the alimentary mixtures, during their fermentation in the first passages; which thence enters the composition of the chyle, and with that Auid is tranfinitted into the blood, there to prevent or correct the putrefactive Diathesis, appears to be chiefly the fixed air of the alimentary substances. But as a rational assent to this medical Lemma, or Affumption, requires a knowlege of the properties of this air, en considered as a constituent principle of bodies, it very logically refers the Reader to the second Estay,

On the Nature and Properties of fixed Air. This is really a curious, and no very contracted, disquisition; which commences with observing, that the excellent Mr. Boyle, who was, in many respects, well acquainted with the properties, and the generation, of air, was unacquainted with it as the principle of cohesion, which theory, our Author fuppofes Dr. Hales to have established, though Haller alone seems to have given fully and clearly into it; all the other systematic Writers in Chemiltry or Physiology, suppoling cohesion to depend altogether on the attraction lublisting between the particles of elementary earth, exclusive of any other principle. To expose the insufficience of this hypothesis, our Author justly remarks, • That if earth were the only caule of cohesion in bodies, there never could be any change in their coinbination,' very rationally subjoining, p. 30,

It is plain, therefore, that the principle upon which cohesion immediately depends, must be of a volatile or fugitive nature, not fized and indestructible, like earth; otherwise the face of this globe would bc covered with dead bodies ; for when a stop is put to the life of either animal or vegetable, they become no


[ocr errors]
« PreviousContinue »