ART. XVI. The Rivals, a Comedy; as it is acted at the Theatre Royal in Covent-Garden. 8vo. I s. 6 d. Wilkie. 1775.

HE Author of this Comedy fpeaks fo modeftly of his performance, prefumes fo little on fuppofed abilities, and fo candidly acknowledges his youth and inexperience, that even remorfelefs critics are inclined rather to promife themfelves much future entertainment from the rays of genius that fhine through particular paffages of his Comedy, than to cenfure with acrimony its irregularities and defects. The fable indeed is neither new nor probable, nor the characters original or well fuftained; but there are many juft obfervations on human life and manners, many beauties of fentiment, and much excellent dialogue. We are forry, however, to fee a young writer of fo great promife, adopting the vulgar error of dreading imitation, and even afferting in his preface that on fubjects on which the mind has been much informed, invention is flow of exerting itself.' The contrary is fo true, that till the mind is ftored with information, invention cannot exift, nor can imagination body forth the form of things unknown, till the poet's eye, glancing over the creation, has enabled his pen to copy and combine the images he has contemplated and admired. Bishop Sprat, towards the conclufion of his Hiftory of the Royal Society, after enumerating many more important advantages refulting from that inftitution, adds, as an appendix, another benefit of experiments; and that is, that their difcoveries will be very serviceable to the wits and writers of this, and all future ages. This (continues he) I am provoked to mention by the confideration of the prefent genius of the English nation; wherein the fudy of wit, and humour of writing prevails fo much, that there are very few conditions, or degrees, or ages of men who are free from its infection. I will therefore declare to all those whom this fpirit has poffeffed, that there is in the works of nature an inexhauftible treasure of FANCY and INVENTION, which will be revealed PROPORTIONABLY TO THE INCREASE OF THEIR KNOWLEDGE.'

Let not therefore our young writers, who would aspire to eminence in the dramatic line, as our Author phrafes it, or in any other walk of literature, let them not (we repeat it) congratulate themselves on their ignorance! let it not be their first wifh in attempting a play, to avoid every appearance of plagiary; but let it be their chief aim to copy nature, and their favourite employment to ftudy thofe great artists who have faithfully imitated her! Horace, it is true, who always

6

Said to be Mr. Sheridan; fon to the celebrated actor.

enforces

enforces the neceffary union of induftry and genius, directs the writer's attention to the living manners;

Refpicere exemplar vitæ morumque jubebo

Doctum imitatorem, & veras hinc ducere voces.

So far, however, is he from countenancing the idea that the progrefs of invention is likely to be interrupted by starts of recollection,' that he recommends the clofett ftudy of the ancient models as the moft effectual means of warming the imagination :

-Vos exemplaria Græca

Nocturna verfate manu, verfate diurnâ.

The Author of the Rivals, being by no means converfant with plays in general,' has incurred the very cenfure he was particularly anxious to avoid, and has exhibited as new, ftale characters and hackneyed fituations, which a more intimate acquaintance with the drama would have taught him to reject. An event which will always happen in iome degree to thofe writers, who think that the want of information will affitt their C.

INVENTION.

FOREIGN ARTICLE announced in our lat APPENDIX (published with the Review for January) fee p. 554.

ART. XVII.

Vermium Terreftrium & Fluviatilium, &c. Succin&a Hiftoria, &c.— A fuccin& History of Animalcules, Worms, and Teftaceous Animals, not Inhabitants of the Sea. By Otho Frederick Muller, &c. 4to. 2 Vols. Leipfic, &c. 1774*.

EV

VERY part of Natural History is now cultivated with with fuch zeal and affiduity by numerous inquirers, that even the animalcular kingdom is not without its natural historians, nomenclators, and claffifiers. But no one, we apprehend, has taken fuch pains to reduce this branch of zoology to a regular fyftem, and to defcribe the numerous fubjects of the invifible world, as the learned and induftrious Author of this performance, who has difplayed equal knowledge and perfeverance in the execution of this difficult task.

In the first volume of the work before us, all the fubjects of this extenfive kingdom, which had before been defcribed as well as numerous others which have not yet been defcribed, named, or perhaps feen, by other obfervers, are regularly arranged under different claffes or genera. In the fubfequent part of this volume, the Author claffes and defcribes the Gens Helminthica; comprehending under that title, as we have already obferved, not only the various kinds of worms, properly fo called, but likewife the different fpecies of polypes, See our laft Appendix, page 554.

M 4

leaches,

leaches, &c. The fecond volume is wholly appropriated to the claffication and defcription of fnails, and other teftaceous animals.

Each article comprehends, in general, a scientific description of the form, organization, and the comparative or real magnitude of each animal, or animalcule ;-its motions, habitudes, or manners, the fynonyms of different authors, the places in which it may be found, and the trivial or popular names of fuch of them as have acquired popular names, either in the Danish, Swedish, German, French, or English languages. References are likewife made to the works of Joblot, Baker, Roefel, and other naturalifts, with refpect to fuch of the animalcular tribes, in particular, as have been delineated in plates. All the Author's defcriptions of this laft-mentioned clafs of animals, which are on many accounts fo difficult to be described, are faid to have been founded on his own immediate and repeated obfervations.

To each of the three principal divifions of this work is prefixed a difcourfe, containing fome general obfervations and reafonings relative to the different fubjects treated of in each of then. From the first of thefe differtations, as being perhaps the most curious and interefting, we fhall collect the fubftance of fome of the most material of the Author's observations.

In this effay on the animalcular kingdom, M. Muller frongly fupports the right of its fubjects to the rank of animals, which has been contested or denied by Buffon and Needham, and very lately by M Guettard; who (in the Novel Litt. Gottingens. anni 1772) has confidered them as mere farinaceous vehicles. Linneus likewife has expreffed fome doubts on this fubject.

This great naturalift, fays M. Muller, who fcrupled not to allow animal life to the Spongia lacuftris, a fubject which has a very doubtful claim to that diftinétion, questions whether the moving particles in infufions are really living bodies, endowed with organs; or whether they are not particles of a faline, oily, or other nature;'-Nomineque fpecifico, adds the Author, infaufto jatis, gentem, innumeris fpeciebus affluentem, in tenebras

damnat.

In oppofition to this doubt, and to the hypothefes of Buffon and Needham, the Author in the firft place obferves, that fimple ocular infpection is alone fufficient to convince the most fceptical naturalift that thefe beings really poffefs animal life. He will fee them moving to different fides of the drop with evident fpontaneity, and changing their direction and velocity, like other animals, at the command of the will. The motion of fome fpecies likewife is fo peculiar to them, as to enable an experienced obferver to diftinguish them, at first fight, from every other

Species.

- fpecies. All of them are obferved to poffefs the faculty of avoiding objects that lie in their way; of fteering clear of each other in the thickeft crowd; of keeping at a distance from any thing offenfive put into the drop; and when the greatest partof it is evaporated, they fhew the utmoft folicitude to protract. their fhort-lived exiftence, by flying to and occupying the small remainder. We may add that, when deferted by the element, we have seen these animated atoms exhibit agonies in dying, as unequivocal as even those of the whale ftranded on the fea-coaft.

M. Muller further obferves, that the motion of the heart and inteftines, and the excretion of the faces, are manifeft in fome of thefe beings, and that, in a few, their copulation is scarce problematical. Thefe, and fome other circumftances which we omit, furely intitle them to a rank in the animal, and not in that neutral or chaotic kingdom, to which they have been condemned by fome; evidently to fupport the interefts of a fyftem, and to establish a new modification of the ancient doctrine of equivocal generation; by deriving their origin from certain active or productive forces, and organical molecules

Having eftablished their title to animal life, we may now confidently proceed to defcribe the different modes of procreation obfervable amongst the animalcular tribes. These are various, and fome of them very fingular; nor are fome fpecies confined to one mode of propagation. Some animalcules are viviparous ; others are produced from eggs; and fome fpecies are propagated by gems, buds, or fhoots: but others feem to poffefs a kind of immortality (accidents excepted) perpetuating themselves, at certain intervals, by an equal partition of their perfons into halves.

We formerly defcribed this laft-mentioned very fingular generative procefs t, of which Bonnet had entertained fome fufpicions, but which appears to have been firft afcertained by M. de Sauffure, in the volvox of Linneus. This animalcule, it was faid, by a gradual contraction of its oval figure in the middle, at length effected a total feparation in that part, and became two complete individuals; between whom, we thought it would puzzle the most casuistical naturalift or genealogift, to determine the rights of primogeniture or filiation. M. Muller here enumerates the various modes in which generation, by equal partition, is effected in different fpecies of animalcules, and even in fome of the larger aquatic animals. In a few of these last, and particularly in the Author's Genus of the Naides, which are vifible to the naked eye, it is effected by a tranfverfe divifion; in others, it is performed by a longitudinal partition: the fiffure, in fome, beginning at each extremity, and, in

others, at one only. We fhall give the substance of the Author's accurate defcription of these procreative proceffes, as obferved in the Trichoda Lepus; fome of which genus are propagated by tranfverfe, and others by longitudinal partition.

In the first of these cafes, a small fiflure is perceived on each fide of the animalcule, each of which gradually extends till they nearly meet; fo that the anterior and hinder parts of the little animal adhere together only by a point. At this very time certain external hairs or filaments, as well as certain moving points within, that diftinguish the anterior part of the whole animal, are plainly to be perceived in the new or future animal. The mother, as the Author denominates the anterior part of this compound being, fwims about, and exerts various movements to difengage herself from her po terior moiety. When this has been effected, the two individuals foon acquire the adult form, from which they fomewhat vary on their first feparation; and each of them proceeds to multiply its fpecies by a new divifion.-From this more accurate account of animalcular propagation by tranfverse partition, the anterior animal appears evidently to be the mother. In the following mode, no distinctive criteria prefent themselves to afcertain the feniority between the halves.

When propagation is effected by a longitudinal divifion in the Trichoda Lepus, the fiffure begins in the hinder extremity of the animalcule; proceeding by degrees through the middle of the body, which is hereby feparated into two equal parts, gradually diverging from each other, and which at length cohere only at the apex. At this time the animalcule exhibits fuch a grotefque and whimsical appearance, that it paffes with an unexperienced obferver for a fingular and unknown animal; especially when, to promote the feparation of the two moieties, it alternately brings them together, and then projects them with great violence from each other. In confequence of repeated efforts, they are at length feparated; and two complete animals appear, of the fame length, and provided with the fame organs, as the adult animal poffeffed before the feparation. The fingular appearances and motions exhibited by various animalcules during this generative process, have given occafion to many mistakes among microscopical obfervers, through their ignorance of the nature and final caufe of it.

In the extenfive genus of the Vorticella, fome of the fpecies, like the Trichoda Lepus abovementioned, are propagated by longitudinal, and others by transverse partition; some of the genus multiply by gems, and others by eggs; and to increase the variety, others of the fame tribe are viviparous.-Such are the various modes by which Nature, for ends totally unknown to us, has fo largely provided for the keeping up of the fingle genus of the Vorticella!