Thee maw! Fe Ona Oe Fe yee ee aye = 2 cong ie ff ted, ( i i WN WORT i Ne HN) ATT Vay v i wii eho Ria a yt tink hin if Ca ayy § ) 1 Wal ae 1 vt Ny } MT at) het ¥ iy i aa Mieniye Witt Piel av ti Wary i hi im Bhan Neve ASN Na GML Nia? Nes, Neue Bn awn a el ! ye f WA TG ON THE Rah : Lea Ah | ae eng Mristort ALS AND VEGETABLES. « \ E 4 ‘ : - *- Be tis MN Eh i r ‘\a i Ae ai , f pe ‘ D ‘a ® i Cx 4 / TRACTS ON THE NATURAL HISTORY or 7 % ANIMALS AND VEGETABLES, TRANSLATED FROM THE ORIGINAL ITALIAN OF Tur ABBE SPALLANZANL “ROYAL PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF PA F. R. S, LONDON, CURIOS. NATUR. GERMAN, BERLIN, STOCK- HOLM, GOTTINGEN, BOLOGNA, SIENA. BY WITH 4 PHYSIOLOGICAL ILLUSTRATIONS, BY THE TRANSLATOR, ( SECOND EDITION. _VOLUME I. ca Crinburgh ; ? PRINTED FOR WILLIAM CREECH AND ARCHD. CONSTABLE, EDINBURGH; AND T, N. LONGMAN AND O, REES, LONDON, . Oe 1803, % ie Rvay: . a ; ‘he ail ue oe ee 4 Aa, TO THE RIGHT HONOURABLE JAMES EARL OF HOPETOUN, VISCOUNT AITHRY, BARON HOPE, LORD LIEUTENANT OF LINLITHGOWSHIRE, ETC. ETC. ETC, THIS TRANSLATION IS INSCRIBED BY JOHN GRAHAM DALYELL: Die} ~ a4 2 ae ; 3 Kk y CadsOaME St OU AaAWAD CONTENTS. VOLUME FIRST. \ INTRODUCTION. e Phyfoological Refiections on the Natural Hiftory of Animals and Vegetables. Fi aaiccck Heat Ro Se II. Seminal Vermiculi - - - XXiii HEL. Death of Meets in Stagnant Air =", See IV. Animals Killed and Revived = XXXVE V. Origin of Mould - - - lv Animal Reproduction - - Ixiii TRACTS: Obfervations and Experiments 6n the Animalcula of Infufions. CHAPTER I. Whether, according to a new Theory of Generation, Animalcula are produced by a vegetative power in matter. Infufions and infufed fubftances ex- ¢ Poked ee Hees AR! ee tet alle. a m qgele ay ~ BIB4A CHAP, viii CONTENTS. CHAPTER II. Whether the influence of heat diminifhes the elafticity of air included in veffels hermetically fealed ; and if it would be an obftacle to the produétion of Animalcula - 4 4 + 3 iS CHAPTER TIE. Eggs and Animals.—Seeds and Plants expofed to different degrees of heat - - - - & CHAPTER IV. trfafion Animalcula and their germs, expofed to va- rious degrees of cold 2 ie i s CHAPTER 'YV. More accurate and extenfive confiderations of the ef. fees of heat and cold on animals a S CHAPTER VI.. fafufion Animaleula expofed to various odours and liquors, to electricity, and a vacuum a“ CHAPTER VIi. Singular mode in which many Animaleula propa- gate - = 2 = - - 13 3t 53 65 98 CONTENTS, ye | CHAPTER VIII. Several Infufion Animalcula are oviparous; fome viviparous ; and all hermaphrodites in the ftricteft fenfe - mT Ne - - - - 169 CHAPTER IX. Animalcula poffefs the real and charateriftic marks of animality - -— = A ge a 173 Two Epiftolary Difertations on Infufion Animalcula addrefed to the author, by the celebrated M. Bonnet of Geneva. Letter I. = = “ . 2 Ps Z 195 Letter II. 2 = a Obfervations and Experiments on the Seminal Vermiculi of Man and other Animals, with an examination of the celes brated Theory of Organic Molecules. Introduction =—s = - * a, sign gi oie]? CHAPTER I. Defcription of the Seminal Vermiculi of Man, and various other animals - = = - 283 CHAPTER II. The preceding obfervations compared with thofe of Leeuwenhoeck.—Confutation of fome opinions — concerning the nature of Seminal Vermiculi 302 ie CONTENTS: CHAPTER III. A brief account of M. de Buffon’s Obfervations on Seminal Vermiculi.—Critical Reflections on thefe Obfervations - - e - - . 320 VOLUME SECOND. CHAPTER IV. Reflections on M. de Buffon’s Obfervations.—Compa- rifon of Seminal Vermiculi, with io Putredinous Animaleula of Semen a Ps - ee ae CHAPTER V. Deduétions from the facts ftated.—M. de Buffon’s Objections anfwered - = - - - I9 CHAPTER VI. ‘ New Experiments and Obfervations tending to deter- mine the nature of Seminal Vermiculi ey. Obfervations and Experiments on Animals and Vegetables con- fined in Stagnant Air. Intredudtion os - - = i ‘ -- 67 CHAPTER I. Infufions—Vegetable Seeds, Animals’ Eggs, and Animals themfelves, fubjeéted to Stagnant Air 69 CHAP, CONTENTS, . xt CHAPTER II. Two principal Opinions on the caufe of Animals dying in Stagnant Air—Whether it lies in the diminifhed Elafticity of the Air - - = 83 CHAPTER III. Whether the Refpiration of Animals in Stagnant Air occafions their Death.—Why the developement of Seeds and Eggs is, in certain fituations, pre- vented by Confined Air - - - - 103 Obfervations and Experiments on fome fingular Animals which may be killed and revived. SECTION I. The Wheel Animal - 8 + . Ig SECTION II. The Sloth, Anguille of Tiles, and thofe of blighted Corn - - - - . < = 159 Obfervations and Experiments on the Origin of the Plantula of Mould = =z o ~ ® « FRACTS é Ri CONTENTS. TRACTS ON ANIMAL REPRODUCTION. Refult of Experiments on the Reproduction of the Head of the Garden Snail. MEMOIR I. Axticizs 1. Anatomical defcription of the Head of to the Snail ‘ - - - - - 216 Arr. 2. Reproduction of the Horns or Antenne 224 Arr. 3. Half the Head reproduced - - = 230 Art. 4. Reproduction of the whole Head - 239 Art. 5. Fads relative to the Reproduétion of the Head of Snails = = = < * 244 MEMOIR II. Introduction - - + - - - - 254 Art. 1. Experiments adverfe to the Reprodudion of the Head of the Snail Sa ere) eae ~ 259 Arr. 2. An account of the Experiments which cor- roborate the Reproduction of the Head - - 263 Arr. 3. Reflections “ = i 4 as 308 Experiments on the Repreduttion of the Head of the Terreftrial Snail, by Charles Bonnet. ; Memoir Ge “Ps hie - - “ i. Sarg Memoir II. Mie bi - - - 34 Memoirs CONTENTS. xili Memoirs on the Reproduétion of the Members of the Water Newt, by Charles Bonnet. Memoir I. = - s ot a cy & 361 Memoir II. c iS ¥ 3 4 if - 392 Memoir III. - - r - - 418 PLATES, PLATES. | Plate 1. Animalcula of Infufions - Vol. I. p. 192 2. Seminal Vermiculi - - 334 3. Refurgent Animals ;. Vol. IL. p. 194 \ 4 ? = 3 - 7 194 5. Plantule of Mould ° . = 214 6. Reprodu€tions of Snails - - 256 a - “is : . > 308 8. 7 _ ay Na 360 9» Reproductions of Newts - 2 390 Os - - " 4ly 31. et ies te e448 gh ¥ ella seit % Desi Sih € ~ ‘- aod \ ry ‘ hagas ; ix <) i. 5 y a We %y re Aaa.) anne * * . w S k inhi ac" i : te ‘ Fate AIS eh Nea % ‘ Pe F ¥, By he , 7 f ey uBR, a4 * ’ RLS te i * 7 ¢ 2 ‘ Bos « BPE uoH x ty MP 4 aae ht, a3 MOD Ph alin acne oie. oe , is Sere ’ " “s r Sie } ‘ se Aili ou aie ig oes so sata e \ ’ cc AS a as PL AF 7 te is i y = ‘ m1 ® ; a Brisk: ANE res i . ma , ne tH tae > MTT SSR ‘ 1 a) , ; , Be Ne Pn / F Tee, g i rita : ‘ a TNs : 7 Say j ‘ . ;. 7 re . an : = igs ; 5 \' tee =e wen % ay " ms! f * ay i : : ONT eae ‘ - Ms | Re “ Wv ae ) "eh ; eet i \ , RENE nt! AM \ ave 3 ¥ i j < *¥ : { Cun 4 i - ' be ian 4 ‘ Pe ‘ f I ; ¥ ’ , j : NM ’ S yom c ; ; big ae , . 4h i ‘ L A ‘ % ay peri < , ? % d ’ 7 7 ¥ : ‘ ‘ aw Ae : i 7 ' { ‘ , n . i y a al - ™~ vr Gi } aes} / ‘ 4 4 voll , * ' as’ : a Re i i et ey ¢ TRANSLATOR’S PREFACE: "Tue acknowledged fame of. the celebrated au- thor of thefe Tracts, and the importance of his numerous difcoveries, are too well eftablifhed to require any additional confirmation here. His name has juftly been inrolled with that of the moft illuftrious European phyfiologifts : and his works will ever remain an emblem of genius and refearch. All bear indifputable evidence of pro- found inveftigation into the phenomena of nature, and of the moft comprehenfive and enlightened underftanding. Probably the following treatifes on the Natural Hi/iory of Animals and Vegetables will rank with the firft of his productions; for the new, fingular, and interefting matter they contain will be an equal fource of pleafure and admiration to the philofophic reader. Vou. i b The ul PREFACE. The unaccountable theory of fpontanéous ge- neration made great and rapid progrefs towards the middle of laft century : it was even embrac- ed by naturalifts of no inconfiderable merit. Mr Needham, in fupporting a fyftem which he firm- ly believed, attacked or mifconfirued fome of the author’s principles, who, in his turn, retorted with uncommon feverity. ‘This controverfy oc- cupied a confiderable portion of the firft Tract, but part of it is here omitted ; for it is certainly needlefs to revive any thing concerning a doctrine now totally exploded. Whoever beholds the -animalcula of infufions, either with the naked. eye or a microfcope, ‘in my opinion, can demand no other evidence of their animation, which was the principal point in difpute. All the other Traéts are preferved entire as in the original. Several notes are fubjoined, chiefly in iluftra- tion of general points, and fometimes in explana- tion of the text. But this is not a mode of writing to be recommended ; for it diftracts the attention from the fubject, and too frequent op- portunities occur of making ufelefs remarks. Perhaps it will always be preferable, if poffible, to connect obfervations of this kind in fuch a manner as to form a brief differtation, which is a much better way for a commentator to illuftrate. The preliminary remarks will in a certain degree fupply Gee PREFACE. iu fupply the place of other elucidations. But an ample field will be found for many more than are there. I muift acknowledge, that I have fometimes been at a lofs to difcover the exact fpecies of feeds which the author ufed for infufions. He feldom or never gives fpecific names; and in Scotland little is yet known of Italian botanical fynonyms. However, itis of lefs importance, as many different infufions will produce the fame animalcula. In my own obfervations on thefe fingular animals, during feveral years, I believe I have difcovered almoft the whole which have been the fubject of the author’s confideration. A _few I have not found, or have been unable to re- cognilfe, Tt will eafily be perceived, thatthe Treatifes on Animal Reprodudtion originally formed no part of the Traéts. ‘Therefore the reader may reafon- ably inquire, why he finds them here.—Such in- veltigations may properly conftitute a fixth fub- je, on which as great learning and ingenuity are beftowed as on the reft. ‘Vhis is a fludy which feems to have made lefs progrefs in Britain than on the Continert; there are few or no original experiments in Englifh, and fome of the follow- ing traéts are difficult to be procured: therefore B 2 i 1Vv PREFACE, it appears right to convert what may be obtained to ufe. There is complete evidence that a deca- pitated {nail will acquire a new head, notwith- {tanding the numerous difcordant opinions and experiments. For this celebrated difcovery we are indebted to Spallanzani, who has confidered the various reproductions of animals more pro- foundly and comprehenfively than any other au- thor: indeed, a very great portion of what is known concerning them we owe to him. The firft Memoir on {nails is entire; but the fecond, where the author enters copioufly into his own défence, is much abbreviated. It is true, all the matter is preferved, but the keennefs and redun- dancy, which ever attend controverly, can give no pleafure to thofe whofe more ufeful refearches are directed to facts. For of what avail are opi- nions unlefs eftablifhed on fatts? Fven the foundeft analogical reafoning is too often to be diftrufted. In thefe Memoirs, feveral redundancies will ac- éur, but it was impoflible to avoid them. M. Bonnet’s whole treatife may appear in this light. However, in one refpect, it may be ufeful, name- ly, from the apparent correétnefs of the engrav- ings. It is by figures chiefly that we are more eafily enabled to underftand fuch intricate fubje€ts of natural hiftory ; M. Bonnet’s are more diverfi- fied PREFACE. ¥ fied than thofe of the other two Memoirs; and as this Memoir was added to the laft edition of the Tracts, independent of the excellence of the matter which it contains, the reader will not be difpleafed to fee it reprinted. Although Spallangani makes - repeated. allufions to an extenfive work on ani- mal reproductions, he never publifhed any thing refpeting the reproductions of water newts, ex« cept what is in his Propromo. ‘The author of his Literary Life informs us, that he confidered the defeét had been fully fupplied by M. Bonnet, and he therefore abandoned the defign of pub- lifhing his Refearches on Animal Reproduc- tions ;—a determination deeply to be regretted by every philofopher. All that is contained in thefe volumes on this fubjeCt, was at firit intend- ed for a feparate publication. It may fafely be affirmed, that we are indebted to the friendfhip fubfifting between the two phi- lofophers for whatever portion of this work is written by M. Bonnet. Their efteem was mu- tual. Spallanzani tranflated La Contemplation de la Nature into italian ; and propofed to tranflate La Palingenefie alfo. However, I believe, the Inquifition oppofed it: at leaft, itis faid, that the tranflation of the work was prohibited by this formidable tribunal. brs The Vi PREFACE. The difference between the ftile of Spallan- _gani and Bonnet is inconceivable. In general, that of the former is natural and perfpicuous : the meaning is eafily comprehended, for it is im a manner analyfed. Bonnet, on the other hand, is commonly prolix, and very often obfcure; and itis fometimes with extreme difficulty that his real fentiments can be difcovered. Several of his writings feem never to have undergone cor- rection ; and a literal tranflation, even abridging the innumerable tautologies and redundancies, founds uncouth in Englifh. Notwithftanding thefe imperfections, he is unqueftionably a great philo- fopher ; he has profoundly inveftigated nature, and: his authenticity is unchallenged. though Spallanzani was reputed the’ firft phyfiologift of the age in which he lived, in one refpect he was certainly moft unfortunate. ‘The truth of bis experiments. was difputed ; nay, his veracity itfelf was called in queftion. Nor was this done by the ignorant, weak, or malignant, who are ufually the firft to labour for the dif- covery of error, but by philofophers of eftablith- ed credit, learned and liberal. Not only has the author’s own defence elucidated any doubt that attended his principles, but the lateft experiments on the fame abftrufe and difficult fubjects have 7 tended PREFACE. Vik _-tended to prove them true, and given them ad- ditional weight. In his whole writings, the author uniformly teltifies the utmoft contempt of nomenclators. Yet we mutt allow that nothing is more ufeful than correct nomenclature; for it refts both, on defcription and phiyfiology.. This fecond quali- fication, it is true, has not met with fufficient at- tention; and the extraordinary anxiety of moft modern naturalifts for claffification, from external appearances, has occafioned the neglect of real phyficlogy ; therefore, the confequence has been continual alterations. Indeed, if both are to be obferved, they will fometimes be at variance with common underftanding. Such as placing bats, whales, and dolphins, in the fame clafs with mankind. ‘Thefe arrangements, however — juft, are at firft repugnant to received opinions ; and many will feel the fame repugnance at ad- mitting medufa, actinia, {nails, and animalcula, into the clafs of vermes. It has often furprifed me very much, that fo few foreign works of high authority are tranflat- ed into Englifh, and almoft never until a con- fiderable interval after publication; nor do I think that any good reafon will eafily be affigned. Affuredly it is not becaufe they are tound prefer- b 4 able gee Vil PREFACE. able in the original, becaufe they are very fel- dom to be procured in that ftate ; and this diffi- culty of procuring the foreign authors is un- doubtedly very detrimental to the literature of the nation: for difcoveries and obfervations, well known on the continent, are frequently a long time dormant here. But the intercourfe of coun- tries, and the rapid progrefs of civilization, will | tend more and more to the diffufion of {cience. PHYSIOLOGICAL REFLECTIONS ON THE NATURAL HISTORY OF ANIMALS AND VEGETABLES, I, ANIMALCULA oF INFUsiIons.—Even in this advanced ftage of fcience, we are intimately ac- quainted with the natural hiftory of only a few of the larger animals which are daily in view. The particular age when they begin to generate is known; we can calculate the period of gefta- tion ; we have learned what food is unfuitable to their nature ; and fometimes it may be difcovered whether they are healthy or difeafed. Thefe ge- neral facts have been attained by reiterated and evident obfervation.— Yet of the fecret vital phe- nomena, K INTRODUCTORY OBSERVATIONS. nomena, and of the life of a favage animal, our knowledge is limited indeed.—The original caufe of exiftence is in the moft profound obfcurity ; we are in the utmoft ignorance why the offspring of an animal aflumes a determinate figure; why the increment of one part is more rapid than that of another; and why the fize of the whole is at laft confined within certain bounds. No fa- tisfaCtory reafon has hitherto been affigned, why the capacity of either fex to generate does not arife until a certain age; for the very different duration of geftation by different females, or the variety in the time of incubation. And al- though we contemplate the progreis of. a difeafe that ends in death, it is feldom that we can either tell what is the real origin of it, or the caufe why exiftence ceafes. Moft of the animals, which have been the fubject of obfervation, we have en- deavoured to domefticate, but thofe that roam in the defert, dwell on lofty mountains, are hid in the earth, or concealed in the receffes of the ocean, are hardly known to us by name.—lIs there any wonder, therefore, that fo many centuries have paffled away, before the properties of beings, al- moft as minute as we conceive the «particles of matter, have been inveftigated ? The animalcula of infufions conftitute a A vl in the animal kingdom, on which the learning and a INTRODUCTORY OBSERVATIONS. xi and ingenuity of philofophers have been equally exercifed. Their infinite multitudes, their varie- ties, the places of abode, and above every thing, their extreme minutenefs, have all confpired to retard our inquiries into their real nature. Let one conceive himfelf,-in a moment, conveyed to a region where the properties, the figure, and motion of every animal are unknown, and he will be able to form fome idea of what infufion animalcula are. ‘The amazing variety of figure be- held at once, and their motions, will firft attract his attention. One is a long flender line, another is an eel or a ferpent. Some are circular, elliptical, and globular, others cylindrical or triangular. One is a thin flat plate, another like a number of articulated reeds. Several have a long tail, al- moft invifible, or the pofterior part is terminated by two ftrong horns. One is like a funnel, an- other like a bell, and many cannot be referred to any object familiar to our fenfes. Certain animal- cula can change their figure at pleafure. Some- times they are extended to immoderate length, then contracted almoft into nothing ; fometimes curved like a leech, ftretched or coiled like a fnake. At one moment an animalcule is inflat- ed, and the next itis flaccid. Some are perfect- ly opaque ; fome fearcely vifible, from extreme tranfparency. Numbers have no apparent or- gans ; and many are covered with tubercles or briftles, Kil INTRODUCTORY OBSERVATIONS. briftles, No lefs fingular is the variety of mo- tion peculiar to each. Sevéral {pecies fwim with the velocity of an arrow ; the eye can hardly fol- low them. Some drag the unwieldy body along by painful exertion, and others feem to perfift in perpetual reft. Ananimalcule will revolve on its centre as the axis of motion, or the anterior part or head is made that axis by another. Some move by undulations, by leaps, or inceflant gyra- tion. In fhort, there is no kind of animal mo- tion, or any other mode of progreffion, that is not practifed by animalcula. The manner in which they propagate is as remarkable. In general, they produce eggs, many, a living foetus, and others, like a few of the larger animals, both ; fome multipiy by a part of the body detaching and becoming a new animal; fome by a tranf- verfe or longitudinal divifion of the body, and others, by the mother burfting to allow her off- fpring to come into the world. Compared with the reft of animated nature, the number of infufion animalcula furpaffes all belief: they are furely the moft numerous. Next are worms, infects, or fifhes ; amphibia and fer- pents, birds, quadrupeds ; and laft, isman. The {pace he occupies on earth is fmall, and the pro- pagation of his fpecies goes flowly on. The hu- zynan female produces only one at a time, that after {NTRODUCTORY OBSERVATIONS. Xiil after a confiderable interval from birth ; and but few during her whole exiftence. Many quadru- peds are fubje&t to fimilar laws ; fome are more fertile, and their fecundity is little, if at all, infe- rior to that of certain birds, for they will produce ten or twenty at once. Several birds will breed frequently in a year, and have more than a fingle egg at atime. How prodigious is the differ- ence, on defcending to fifhes, amphibia, reptiles, infects, and worms! Yet,among them, the num- bers cannot be more different. According to naturalifts, a fcorpion will produce 65 young ; a common fly will lay 144 eggs; a leech, 150; and a fpider, 170. I have feen a hydrachna pro. duce 600 eggs, and a female moth 1100. A tortoife, it is faid, will lay 1coo eggs, and a frog i100. A gall infect has laid 5000 eggs; a fhrimp 6000; and 10000 have been found in . the ovary, or what is fuppofed that part, of an afcarides. One naturalift found above 12000 eggs in a lobfter ; and another above 21000. An infeét, very fimilar to an ant, has produced 80000 ina fingle day; and Leeuwenhoeck feems to compute four millions in a crab. Many fithes, and thofe which in fome countries feldom occur, produce incredible numbers of egos. Above 36000 have been counted in a herring, 38000 in a fmelt, 1000000 in a fole, 1130000 in a‘roach, 2009000 in a fpecies of ftureeon, 342000 ina carp, XIV INTRODUCTORY OBSERVATIONS. carp, 383000 in a tench, 546000 in a mackrel, - 992000 in a perch, and 1357000 in a flounder. But of all fifhes hitherto difcovered, the cod feems the moft fertile. One naturalift computes - that it produces more than 3686000 eggs; an- other, goooooo; and a third, 93444000. Here then are eleven fifhes, which, probably in the courfe of one feafon, will produce above thirteen millions of eggs ; which is a number fo aftonifh- ing and immenfe, that, without demonttration, we could never believe it true. Perhaps the innumerable multitude of animals in exiftence is lefs influenced by the numbers produced at a time than by frequent and early propagation, by the hazard of deftruction to which the young are expofed, and alfo, it is pof- _ fible, by fome females being more numerous than males. Many infects generate but once in their ‘ whole lives. It has been calculated, that two females, of the animals moft loathfome-and dif- — gufting to the human race, may fee ten thoufand defcendents in eight weeks ; that above fourteen thoufand may, in the fecond generation, come from a fpider ; and a common flefh fly have feven hundred and forty thoufand young in the third month. None of thefe animals are at firft very fertile, compared with others. But what are all | their INTRODUCTORY OBSERVATIONS, xv their numbers in comparifon to invifible animal. cula and vermiculi? One hundred and fifty millions have been computed in the milt of a fingle fith, How does it happen that the earth is not over- run by animals, and that they find food fufficient for the prefervation of life? Ina day, an immenfe legion will fometimes arife, carrying famine and defolation along with it.—To preferve the re- quifite balance, there mutt be deftruétion propor- tioned to propagation ; and the wifdom of Nature feems to have provided for it in a certain degree. The animal, its ege, or the young, are all liable to perifh ; and the more flages it has to pafs through before maturity, the greater hazard does it undergo. Many females produce theufarids of eggs, without any commerce with the male : it often happens that thefe are never fecundated, er a very fmall portion of them, if external fe. cundation fhould take place. The young, in their tender ftate, may either be deftroyed by the elements, or become a prey to thofe {tronger than themfelves. From their various metamorpholes, they are liable to perifh by difeafe, or from un- fuitable fituations. Therefore, comparatively - fpeaking, few come to maturity. The number of butterflies is very inconiiderable, in proportion, to Xvi INTRODUCTORY OBSERVATIONS, to the eggs: few frogs are found near a pool which has been black with tadpoles. Let a leaf, or a particle of animal fubftance, fall into a little water, myriads of animalcula will be produced ; but fimple evaporation of the water, an event that muft enfue, is inevitable deftruction to the whole. Although the period of exiftence is li- mited, few animals die a natural death. The war, which inceflantly rages among the whole, is a never failing fource of deftruction. The ftronger prey on the weaker ; and thefe on ani- mals that are lefs powerful than themfelves. ‘The juftice of Nature might be arraigned: Why are fome provided with horns, tufks, or poifon, while others have no fuch means of defence? Thou- fands of animalcula are apparently but a fimple veficle, without vifible organs external or inter- nal: they burft on contact with the air alone. All this deftruction is neceflary ; the earth would be overftocked ; and even thofe animals, now living in amity, would make each other a prey. Death muft thus be the indifpenfible attendant on life, unlefs propagation were to ceafe. The ftru€ture of fome animalcula, fuch as it appears to us, cannot be more fimple; but the organization of many is certainly very complicat- ed, no lefs fo than that of animals a thoufand times INTRODUCTORY OBSERVATIONS. XvIii times their fize. Several naturalifts have affum- ed the /implicity of organization, as the means of explaining different phenomena exhibited by ani- mals. ‘To me this feems moft fallacious reafon- ing. The organic ftructure of one animal is fimple, only when compared with another known animal. If it lives, it is perfe€t in its kind. Be- caufe no heart, lungs, brain, or nerves, are vifi- ble, we can feldom pofitively affirm either that thefe organs do not exift, or that there are no other parts which perform the functions belong- ing to the mof{t important of them. Indeed, in the fimple animals before us, they may be fo di- verfified, difguifed, and incorporated or partition- ed into its fubftance, as, feparately, to be invifi- ble or irrecognifible, but, collectively, capable of performing every vital function. Some may have lefs neceflity for the important organs which we behold in the larger animals. A muf- cular heart is not equally effential to all that even have one. In general they inftantly die, when deprived of it; but the life of feveral, thus muti- lated, endures longer than that allotted to certain animals in their moft perfect ftate. The pulfa- tion of one heart will ceafe the moment that it is wounded ; another will beat long after being torn from the body. Some agents, deftructive of life, will. deflroy its irritability ; others will produce no fenfible effect. Penetration of the hou. 1, c brain XVlll INEFRODUCEORY OBSERVATIONS. brain will often occafion inftant death ; but va- rious animals will live long, not only after the’ whole has been fcooped from the cavity of the fkull, but after the head itfelf is cut off. In the larger animals, where diffeGtion may be ufed, it isin the power of the anatomift to lay every mufcle, tendon, and blood veffel, bare. In thofe fo mimute as infufion animalcula, where, inftead of each part, the entire whole is in gene- ral hardly vifible, the philofopher muft fome- times be fatisfred with the moft rational induc- tions from what he beholds, and analogical rea-’ foning, if that is ever to be admitted.—The dif- ferent functions of animalcula are probably per- formed by means analogous to thofe of other animals. The courfe of fome, which are without: perceptible external organs, proportionally ex- ceeds the fwifteft flight of birds ; confequently, they muft have confiderable ftrength. Whether their motion proceeds from curvature, leaps, or undulations, it can only be effected by impulfe: againft the water; and we may reafonably infer, that fome mufcular movement is the principle, or that the ftrength proceeds from fomething cor- refponding to mufcles. The great fource of mo- tion among worms and aquatic animals, deftitute of feet and fins, is undulation. In this manner is the progreflion- of all ferpents, eels,. and many other INTRODUCTORY OBSERVATIONS. xix other reptiles. No evident curvature is feen in the body of a fnail; but in the belly are fuc- ceflive undulations, by which its peculiar pro- greffion is performed. It is more convincing, that animalcula have mufcular parts, and perhaps joints formed of membrane, or a fimilar fub- ftance, when we can aétually obferve fins, feet, or fibrilli. Many which we fuppofé deprived of them, really are not fo; and in others, they are fo minute, flender, or tran{parent, or fo much of the fame colour as the fluid they inhabit, as feldom ot never to be vifi- ble. Indeed we often fee particles, in an infu- fion, carried along, at a diftance from the animal- cula, by fome invifible hair: i When an animal is called imperfe&t, we mean, that it wants organs with the ufe of which we are acquainted. External impreffions are cer- tainly the origin of ideas; and there’ is reas fon to believe, that mind originates entirely with the ufe that can be made of the fenfes. Undoubtedly we can form no conception of any object, without the intervention of fome of the fenfes: and, although the mind may wander through all the immeafurable field of imagina- tion, {till it can invent no new idea that is with- out any chain or link to what is fuggefted by the fenfes. Thus, if it is poflible to conceive that a ¢2 man XX INTRODUCTORY OBSERVATIONS.. man might be born without any of the fenfes, we cannot figure how he could have mind, or be ca- pable of diftinguifhing objects. But there are ma- ny animals which want fome of the known fenfes, and are {till capable of volition, choice, and feveral of thofe fenfations which we afcribe to the moft perfect. It is not evident that they labour under much inconvenience, where certain organs are entirely wanting, or derive equivalent advan- tage, where they abound: ‘The variety of organs ig more effential than the number.—The flight of an infe&t is as rapid with two wings as with four: vifion is as acute with two eyes as with eight: progrefhon is as quick with fix or eight legs as with an hundred. Indeed it is difficult to fay what is the ufe of fuch a redundancy of organs, at leaft, if we judge from fimple appear- ances. Some animals, which have only fix legs. at firft, acquire an additional pair every year of their lives. ‘There is one {pecies with eight legs, when full grown, in which the third pair is want-. ing at firft; and another, with fix pair originally,. and a feventh is afterwards acquired. » More than five fenfes may exift; nor is there any abfolute neceflity for limitation to that num- ber. In various animals, there may be others fo complicated or uncommon, as to be totally incomprehenfible by the human mind ; and they may ~ INTRODUCTORY OBSERVATIONS. XX! may be tranfmitted through channels very dif- ferent from thofe known to us for the tranfmil- fion of fenfe. Hearing and fight are very un- certain in whole claffes of animals; the ears of very few infects have been difcovered ; fome mol- lufcae and worms feem hardly to be fenfible of found. In infeéts, which form fo great and beau- tiful-a part of the creation, vifion is undoubtedly very obfcure. No organs of vifion are found in an infinity of worms ; and thofe that have eyes feem to make very little-ufe of them. Although many infects are fenfible of the impreffions of light, I doubt whether they are capable of the perception of objects, or guided towards them by vifion ; even the wonderful operations of the bee are per- formed in utter darknefs. There are fome infects, however, that are fenfible of the prefence of adja- cent objects, and actually recognife them as l have demonftrated by experiment. -One fenfe may certainly fupply the place of another, which we fee in the larger animals. A bat, deprived af fight, will traverfe the fame courfe, and avoid the fame obftacles as before. Thefe creatures fly through openings, nay, difcover new ones, and without any embarraflment, pafs through them. Some naturalifts thence concluded, that bats had afixth fenfe; fome from experiment afferted, they were guided by hearing ; and others, that exce!-: five delicacy of feeling rendered them fenfible of rea the XXil INTRODUCTORY OBSERVATIONS. the prefence and direction of objects. Innume- rable inftances prove, that one fenfe, either in a natural ftate, or well practifed, may ‘fupply the place of another. Thus, apparent fimplicity of organization can neither be an argument for explaining the phe- nomena prefented by animalcula or the fimilar claffes of animals, fuch as propagation by fhoots or divifion, refufcitation, reparation of the loft parts, as has been fuppofed peculiar to certain animalcula. But with all this apparent fimplici- ty, they poflefs every charatteriftic requifite to entitle an animal to be called a living being. A flight inveftigation of their nature is alone fuf- ficient to eftablifh the fa& ; for there is fcarcely any phenomenon among known animals, that does not exift among them ; and they exhibit ma- ny which feldom or never occur in any other | race. It isa prevalent opinion, that animalcula may be difcovered in rain water with the microfcope, or in that of the pureft fountain. This is an error. I have never once found them in the courfe of innu- merable obfervations ; and the great animalculift Muuuer himfelf fays, they are very rare. That they may exift in thefe fituations, is by no means impofible ; they may be invifible in air, and be- come INTRODUCTORY OBSERVATIONS. xxiii come vifible in water. Though imperceptible -by our fenfes, they may be fufpended in the air :as their native element ; and, if it was not for the exceffive delicacy of their parts, and the difficulty of obfervation, they might be rendered vifible by the interpofition of different mediums ; —and here imaginatiqn may figure beings of an- other kind, which, by an interpofing medium, may in the fame manner be brought into view. Some animalcula of confiderable fize are feen with the utmoft difficulty, from extreme tranf- parency ; it is only an accidental inflection, or an alteration of the ufual direction of the rays of light, that renders them vifible. Hi. SeminwaL VermicuLi.—Three great and important points are to be confidered in animat- ed exiftence ; the mode of an animal’s origin and introduction into the world ; the duration of life ; and the manner of it’s death. What we daily behold, events and objeéts continually familiar to us, make little impreflion ; and, if there is any no- velty at firft, it foon wears away. If we refleé on the phenomena of nature, and inquire into the original caufe of life, its prefervation and end, an infinite and unaccountable variety is prefent- ed; and although we may be inclined to give phyfical reafons in explication, or feel an interna! convidion that none other will apply to certain c 4 cafes, KXiV INTRODUCTORY OBSERVATIONS. cafes, it muft be acknowledged, that the boundlefs empire cf nature has neither been com- pletely explored, nor reduced within determinate ‘limits by human underftanding, and ee never will. ‘Seminal vermiculi are a race of animals whofe origin, exiftence, and ufe, if they are of any, are all equally myfterious. Their origin is even more wonderful than that of the numerous other worms inhabiting the bodies by which they are nourifhed. Every thing contributes to the difficulty of inveftigating their nature. The ter- mination of life, or the cruel mutilations that muft be employed to view them in their native abode; the ravages and diforder that fuch ope- rations muft occafion; and their extreme mi- nutenefs (for it has been computed that the dia- imeter of fome does not exceed one hundredth part of the thicknefs of a human hair) render it furprifing how fo much of their hiftory has been difcovered. But the period is yet diftant, when every kind of propagation fhall be known. Two thoufand years ago, the generation of eels occu- pied the attention of naturalifts, and it is ftill ob- fcure.—The chief difficulty which attends our comprehending the origin of feminal vermiculi is their appearance only at a certain age. Where do they exift before this term arrives ? The germ or primordium INTRODUCTORY OBSERVATIONS. xxv primordium may conftitute a part of the animal it- felf: it may remain entire, though incapable of ex- panfion, and not be liable to decay for a feries of years; then, when the fluid which it fhould naturally inhabit is fecreted, fome of the nu- merous germs, which we may well fuppofe diffe- minated throughout the body, will be unfold- ed there, though the circumftances neceflary for their developement are feldom or never found elfe- where. Inthe fame manner, it is not impro- bable, are the numerous worms inhabiting the human body produced. The egg is conveyed into the body, or tran{mitted by the parent; and, when in a fuitable fituation, it expands. Yet this reproduction is myfterious, when com- pared with that of other animals. The fame rules, with little variation, regulate the propagation of mankind, quadrupeds, and birds. Fifhes and amphibia in general generate in a mode peculiar to themfelves. Infects ap- proach in fome refpects to the higher orders of animals ; but defcending to the innumerable and various claffes of worms in all the branches, no- thing can be more diverfified. Some divide into pieces, and each becomes a new animal ; others fend forth buds, which grow complete like the parent, and thus perpetuate the {pecies ; fome pro- duce living young ; fome eggs; and a few, both eggs and young. The “XXv1 INTRODUCTORY OBSERVATIONS. The theories of generation which thefe pecu- liarities have created are various; and all, even the moft inconfiftent and chimerical, have had partifans. Perhaps the fame difficulty does not attend a probable conjecture, not to go fo far as explanation, of that generation, which is effected by means of a fluid and of eggs. ‘When the fe- male approaches maturity, and often long before it, fubftances refembling eggs, or which really are fo, appear ; and in the male is fecreted that parti- cular fluid which is peopled by numberlefs ver- miculi. Invmediately after they were difcovered, the. charge of perpetuating animated beings was com- mitted to them: it was generally believed that e- very animal originated from a vermicule. But it is now univerfally known that the foetus belongs to the mother alone ;. that it pre-exifts fecundation ; and lies dormant until it is called into exiftence. Eggs have been rendered prolific; and animals, which require copulation to propagate their young, have been artificially fecundated, that is, without interpofition of the male. It is even faid that this ftrange experiment has fucceeded in | _ mankind. Still it is to be explained, why of twenty or thirty eggs, as in the human female, only one is impregnated at a time, and why ten or fifteen may be impregnated in a female quadruped ; more efpecially, if generation is effected by ab- forption, INTRODUCTORY OBSERVATIONS. xxvii ferption, as it is moft natural to believe. Is it be- caufe only one ovum is in a ftate to be impreg- nated in the one cafe, and almoft always more than one in the other? Whatever is the truth, it is evident that feminal vermiculi have no’ con- cern in generation, both becaufe it appears that fome feminal fluids are entirely deftitute of them, and not the lefs fecundative on that account; and although the whole are dead, their native element has loft none of its prolific virtue. Since indifputa- bie obfervations prove, that various animals actual- ty exift in the mother before fecundation, how do they originate there? Does every germ include an- other germ; that a fmaller one ; and in this man- ner involving fucceflive germs to infinity ; fo that athoufand years ago, beings which have now paffed through a thoufand generations, then ex- ifted, though the term of evolution could not ar- rive until a thoufand changes were undergone? Can we conceive, that at a time beyond the pow- er of imagination to reach, a germ exifted ; that we ourfelves, the prefent generation of mankind, were in being, under any figure, however mi- nute ; that, until the maturity of the preceding generation, our bodies could never expand into perfe& fhape and organization.—Or, is it more rational to fuppofe, that at the age of puberty, fomething is fecreted. by the mother, that there is fome affimilation of parts which will form a fe- : tus ; MXVIll INTRODUCTORY OBSERVATIONS. tus; that there is fome generative power developed with age, which can produce a germ capable of being fecundated by the male. Difcordant opi- pions like thefe have divided the moft celebrated philofophers ; ingenious arguments have been gi- yen for each; and if infinite involution is the more generally adopted, perhaps it is becaufe the expanfion of parts in miniature is lefs repugnant to the mind than creation.—Yet changes cer- tainly take place in the bodies of animals, which may almoft be called creation. New parts are acquired; though thefe may be derived from other exifting fubftances, ftill they form a part of the body. The cartilages of a foetus undoubtedly do not contain principles exactly the fame as the bones of an adult. Solids may be involved in other fo- lids ; but.it was never faid that fluids could be in- : volved in fluids. The blood, the milk, the bile, urine, and the numerous other fluids in the human body, muft be derived from other fubftances, be- caufe the quantity of any one is fo {mall in the foetus ; not to name that prolific fluid which does not exift before a particular ftate at which the body arrives. The folids muft alfo acquire new parts ; increment in fize may be effected indeed, by expanfion alone, but no additional weight will be gained.—But this is entering on the pro- found theory of increment. Thefe facts bear fome diftant refemblance to creation, notwith- fanding they are only the affimilation of one fub- {tance {NTRODUCTORY OBSERVATIONS. xxiz ftance into the parts of another. Every fyftem of generation is accompanied by difficulties al- moft infurmountable. We have penetrated fome of the myfteries, but the veil is not entirely. re- moved. Though the germ belongs to the female alone, the male has an active fhare in the expanfion and modification of its parts. The eyes, the voice, the colour, nay, the whole appearance, often re- femble the father much more than the mother. However, in confidermg this matter on 4 great fcale, and neglecting the peculiarities of individuals, all animals have a greater refemblance to the mother. The flat nofe, the woolly hair, and thick lips of a negro will be tranfmitted to his offspring by a European woman: and the high features, long hair, and light colour of a European father will be tranfmitted in fome mea- fure to the child of an African mother. Fhe a¢tive part of the father is more confpicuous in the ge- neration of hybrids. In the offspring of the afs and the mare, the goldfinch and canary, or the canary and linnet, fome of the parts peculiar to the female are altered, while thofe belonging to the father are preferved almoft entire. He com- municates fomething, whatever it may be, that awakens exiftence in the germ, is affimilated into itfelf, and regulates the formation and appearance of ‘Xxx INTRODUCTORY OBSERVATIONS: of its body. But the greateft fingularity is, that certain parts fhould be received, and others re- jected: that although the father is deprived of thofe very parts which prove the offspring his, it will have them all. Notwithftanding both pa- rents fhould be maimed or mutilated, the germ is perfet, and the embryo will exhibit none of their imperfections. What an immenfe fund for experiment and obfervation is here! Sometimes imperfections are ,hereditary ; but thefe are rare and uncommon cafes: and it is much more re- markable when an exifting imperfection pafles one generation and affects the next. Deformity of the perfon is often tranfmitted to a fueceeding race: we have known a vice in the conformation-of the organs of hearing and fpeech in a whole fa- mily, and fometimes {everal children born blind. Thefe imperfections, on inveftigation; are fre- quently found in the relations of the parents. Confidering the little progrefs of knowledge, and the rude hypothefes of generation, it is not at all furprifing that the origin of animals was afcribed to feminat vermiculi when they were firft difcovered: and this would have acquired additional credit had it been. known there were pores in the integuments of the germ or egg which vermiculi might penetrate-—Let us _con- fider an impregnated egg. It confifts of a trans {parent INTRODUCTORY OBSERVATIONS. XxX fgarent vifcous fluid, furrounding a yellow liquid contained in another envelope; nothing more is vifible. If the egg is expofed to heat, it is of no importance whence derived; if attaining a certain degree, appears an irregular vermicular figure, without any determinate parts. But this is the rudiments of the chicken. A red point next becomes vifible, which is the heart: then the eyes: and the bill are unfolded: the embryo gradually increafes; it grows a perfect animal, and-burfts the fhell. Ina manner nearly analogous are the original evolution and increment of the hu- man living foetus. A tranfparent veficle is detach- ed from the ovary by impregnation ; it is depofited ’ in the womb ; ali the parts of the human. body appear ; and what is in one and twenty days ac- complifhed in the chicken fucceeds in nine months: the perfect fcetus is formed. How this could be affeéted without any fenfible pri- mordium, confounded naturalifts, (for then it had not been proved that the germ belongs to: the female) and. when they faw a living animal furnifhed by the male, they eagerly adopted it as the principle of exiftence. TEL DeatrH of ANIMALS IN STAGNANT Air.—Long before philofophical experiment, it was probably well known, that the life of an ani- mal confined where there is no admiffion of frefh air, / 4xxll INTRODUCTORY OBSERVATIONS. air, or where the circulation is impeded, will be deftroyed ; and that plants in fuch a fituation will droop and die.—Late refearches in chemiftry have difcovered various invifible fluids produc- ed by different fubftances, which are fatal to the animals that refpire them. Some are fo deftruc- tive as to occafion inftant diffolution ; m others, an animal may linger long, though it will at laft perifh under their deleterious influence. Nay, eminent philofophers have fallen a victim to ha- zardous experiment on themfelves: and feveral have efcaped after the moft imminent danger. | So ufeful is atmofpherical air to the conferva- tion of life, and fo dependent is life on its influ- ence, that none of the animals, with whofe na- ture we are acquainted, can exift without it entirely : and if fome do fupport privation of air better than others, {till they languifh, and at length will die. ‘Thofe inhabiting waters, and feldom come to the furface for refpiration, perifh when the water is deprived of the pure air which it contains. Atmofpherical air is not a fimple fluid ; it is a combination of various fluids ; fome of which, in a decompofed and feparate ftate, are better calcu- lated to fupport life, at leaft for a certain time, than the reft, but none except itfelf has yet been found INTRODUCTORY OBSERVATIONS. Xxxifl found perfectly innoxious, nor any one equally beneficial: The principal ingredients are faid to be azotic gas, oxygen, carbonic acid, and water. Azotic gas and carbonic acid are moft pernicious to animals, and the former conftitutes two-thirds of the whole. By refpiration; a chemical pro: eels takes place, both in the fyftem of the refpir- ing animal and in the air. A change is produc- ed in the blood, and animal heat is promoted. But the alteration that fuceeeds in the fluid re- fpired is of greater importance, for it is that’ which oceafions death in whatever manner it may operate. ‘The oxygen, or pure vital air, is confumed ; an addition is made to the carbonic acid gas, and almoft all the azot is left. Such are the principal changes effected by refpiration. When this goes on in the open air, the continual renewal of the pure parts, and the purification of thofe unfit -for ufe, the emanations and combina- tions of what arife from the fubftances in which analogous operations are maintained, render it again capable of being refpired without injury. When the vital air is confumed,:and the noxious part remains behind, the pernicious effects imme! diately become vifible. The manner in which death enfues, like moft profound inveftigations, has divided the opinion ox philofophers. ioe ea illest Various ot XXXIV INTRODUCTORY OBSERVATIONS: Various gafes produce an. alteration in the ftate of the blood: experiment, it is true, has been chiefly directed to blood after proceeding from the body of the animal, andthe difficulty of the fubject has: hitherto prevented- a full confidera- tion of what are the principal phenomena on that which ftill continues to flow during life. Whe- ther or not the change there produced is fufhi- cient to deftroy the animal, the operation of gafes. on the mufcular and nervous: fyftem is very con-- fpicuous, and efpecially on the former, perhaps,. becaufe it may then be more eafily recognifed.. Animals, at the fame time, in fome inftances cer-. tainly die from abfolute fuffocation ; for the ex- ceflive irritation produced by gafes will clofe the: entry to the lunes, and death enfue before one: infpiration is completed. ‘Fhe general operation is molt probably on.mufcular. irritability and the. rerves, more efpecially when we refle& that the ee refpiring fo very little, as fome are known to do, can not efcape the pernicious confequence of refpired air. Yet we muft admit, that if they refpire at all, which it is moft likely they do, by- abforbing air from water, if they are aquatic ani- mals, they will alfo abforb exhalations, and thus. be deftroyed. | Drowning and ftrangling are equally fatal to. life.as fuffocation in mephitic vapours; but, the’ irritability \ INTRODUCTORY OBSERVATIONS. Xxxv irritability of the heart is much longer preferved in drowned and {trangled animals than in thofe that have perifhed in gafes. Much light has been thrown on mufcular irritability finee the difeovery of Galvanifm ; for by that means a {park of life has often been found when it was thought totally extinct. The lofs of irritability depends in a great meafure on the nature of the fluid in which the animal has died. By fome, it will be altoge- ther deftroyed, and others will only weaken its power. Drowning an animal fufpended by the feet, is entirely deftructive of irritability, alfo the vapour of charcoal and other gafes; but azotic gas and atrhofpherical air only diminifh, they do not extinguifh it; and the heart of an animal, killed by its own refpiration, beats long after- wards. ‘YVhus the difference is very great both in the fuddennefs of death and the effect upon its body, according to the medium where an ani- mal has perifhed. -But it fhould be confidered, with the utmoft attention, whether any of the characteriftie tymptoms precede, accompany, or follow death: From nutmerous experiments, it appears that death, in ftagnant air or in mephitic gafes, may proceed from fuffocation, from injury of the muf- cular fibre, from affections of the nerves, or all three combined, or perhaps from the che:nical d 2 change XXXV1 INTRODUCTORY OBSERVATIONS.- change produced on the blood by refpiration be- ing obftructed ; but itis not evident that conclu- fions from experiments are coincident, or that the real caufe is fully eftablifhed.. IV. Animaus Ki.tepD aND Revivep.—We are loft in aftonifhment while we contemplate the. nature of Lire: the deeper our inquiries go, the farther does the object feem to recede from us. Wecan account for the deftruction of life, when — the reciprocal harmony. of the parts of an animal is deranged :. the functions.of the moft important. organs are interrupted, and death muft enfue; but how life is maintained is a profound myftery.---An. animal originates, its parts unfold, and it vifibly. lives.. At firft, the interpofition of. a parent is, neceflary to adminifter the nutritive matter, for. its own organs are too weak and imperfect. At length, they acquire {ufficient power to receive nu-. triment; the animal 1s. detached from its.parent,. and lives for itfelf. It gradually approaches to- perfeCtion, new parts are.expanded, and thus may it remain for years with little or no fenfible. alteration. Then the organs begin to evince perceptible fymptoms of decay: certain parts in- creafe, change, or diminifh: they become de-. ranged, and incapable of performing their refpec- tive offices: life grows feeble, the animal Jan- euifhes and.dies ;, and what conftituted its perfo. nality ’ INTRODUCTORY OBSERVATIONS. XXXVii nality vanifhes in air. Such is the termination of exiftence by age: but how {mall a portion of the animated creation attain the time! Often, during the vigour of youth, in the height of ac- tivity and fenfation, the chain will be diflolved without any external caufe ; the thread is cut; fomething feems.to depart; and the moft beauti- ful work of nature haftens into hideous corrup- ‘tion. To affirm that a being, whofe animation has been fufpended for an immoderate length of time, even for years, can, in virtue of certain condi- tions, be revived, has fo fingular and paradoxical an appearance, that reafon finds it repugnant to admit the faét. But to produce an animal which "has been ftiffand motionlefs, withered, disfigured, and contracted; utterly incapable of any corporeal function, and. the operation of its organs at an end ; to produce this animal, and, by a particular treatment, to make it renovate every action that it could ‘perform before ; to fee nutrition, digeftion, and generation carried on, not only will it bear perfect conviction to the mind that it has come from a {tate which, if it was not death, certain! y cannot be called life, but that it again lives as completely as before its animation was fufpended or deftroyed.---Some animals in the world enjoy this wonderful prerogative. They originate, ar- rive at maturity, and maintain the vital functions: d 3 their MXKVIil INTRODUCTORY OBSERVATIONS. ‘their native clement is a fluid, and they are natu- rally moift ; but deprive them of this element, or allow them to dry, they become motionlefs, they contract, wither, and die. Thus may the animals remain one year or ten; then let moifture and the other requifites be fupplied, their members fwell, life returns, and the animals become as lively and vigorous as ever. It is reafonable to expec that fo remarkable a deviation from the courfe of nature fhould be h- mited, and the privileged animals uncommon- ly few. Still they are not fo rare as to prevent the truth of the phenomenon from being amply eftablifhed. Hitherto none of the larger animals have been found which are endowed with this fingular property.—Nature, as if to veil that which is fo fondly cherifhed in idea by mankind, feems to have beftowed it only on the moft mi- nute of her creatures.—The wheel animal, vari- - ous microfcopic eels, and the floth, may all die ~ and be revived. The exceflive fcarcity of the laft has prevented naturalifts from inveftigating the utmoft limits of its refurgent faculties. No one, ex- cept Spallanzani, fo far as I know, has ever been able to difcover it. In this remote kingdom, where the ftudy of animated exiftence is yet in infancy, I have found three, perhaps four vatie-. - ties of the floth, all evidently belonging to the fame aoe of this wonderful animal, or of a race analogous 5 , INTRODUCTORY OBSERVATIONS. XXxik analogous; but whether poffefling the fame pre- ‘rogative I have not yet been able to aicertain. “OF the fourth, I fpeak with diffidence ; for, with- out long inveftigation, we mutt hefitate in afcribing animality to a being whofe length does not equal the thicknefs of a human hair, which fearcely -ever exhibits perceptible motion, and is not once to be found in a thoufand obfervations. Whether an animal may. actually die, and af- terwards be revived, has been the fubje&t of much controverfy ;. equally fo as the fymptoms pre- ceding and attending death. Putrefaction is, by common confent, regarded as the moft infallible fign of diffolution, though it will fometimes com- mence during life. But ‘many animals dry up, and wither, and-become as hard as wood without putrefaction ever appearing in the flighteit degree. ‘Next to this, the want of irritability is confidered certain evidence of death. -Yet the abfence of it will not always prove an animal dead; for life often remains when there is no fenfible irritability ; ‘and one ftimulant will awaken vitality, while the ufe of all others.is vain.—In the fame manner as particular ftimulants are incapable of awakening dormant animation, neither can methods deftruc. ‘tive of it, in its utmoft vigour, in one inftance, af- fet it at allin another. Undoubtedly we fhould fuppofe the moft efficacious methods of deftroying animals, are depriving them of nutriment, or de- d privine 4 priving Ne xi INTRODUCTORY OBSERVATIONS. priving them of fome organs which feem moft im, portant in executing the vital functions. | Whe; ther life is in thefe fituations extinguifhed by the fame means, or whether it is extinguifh- . ed in every cafe, by exciting 2 aa will impair exifting irritability, is left to greater phyfiologifts. But until the principle of life is dif- covered, which, according to fome, is the union and reciprocal adtion of the parts in refitting diffolution ; or confifts in the blood ; in a particu- lar aura, like the imaginary aura feminalis ; in fomething refembling electricity ; in irritability, or the exiftence of nerves ; all reafoning on what affects its creation, prefervation, or deftru@tion, muft be unfatisfactory. One thing is certain, that the death of one part is often the neceffary confequence of that of another ; that the death of the heart may occafion the death of the brain; and the lungs will die when the heart is dead. Mankind can ill fupport the privation of food. It is true there are fome wonderful {tories of abfti- nence, in the records handed down to our own time ; however, thefe in general may be rather af- cribed to the love of impofture, and that anxiety to deal in the marvellous, which fo eminently charac- terifed the darker ages. Still, abiding by authentic information, and trufting to veracious accounts of modern date, men have fubfifted on a quantity of food fmall beyond belief; and have even exifted | incredibly - INTRODUCTORY OBSERVATIONS. ~ xli incredibly long without any at all. Captain Bligh of the Bounty, failed near four thoufand miles in an open boat, reduced to the utmoft ex- tremity for want of provifions : fometimes a bird, not many ounces in weight, was the only food for feventeen people ina day. Fourteen men and women of the Juno, wrecked an the coaft of Ar- racan, lived twenty-three days without a morfel of food. On the fifth day after the fhipwreck, two people firft died of want. Animals, Redi obferves, do not perifh from hunger fo foon as is generally belicved, The pe- riod of their death is very various. Houfe and field rats never lived with him three days; ca- pons lived feven, eight, or nine ; a civet cat lived ten ; wild pigeons, twelve and ihirteen days; an antelope, twenty, and a very large wild cat, the fame time. B : § sy hs ahs r art x vig ; He, v2 \ i 5 \ 4 x 5 ’ ? ins d Pines . ¥ ‘ ; r s i i Jae my ~ 5 ; M j x * d y ) Gt \ » ‘ i \ s ‘ bales Par vi ‘ 5 4 SEE: el aan: v > e tie - , ~ ; } . 4 Y x P iy hers ‘ ore e \ v u % we afin ran * Sh aks * SY wks A ea 5 SNA - b. Wie rh Hs 4 ; ‘y \ , 5 { ¥ . yh - - ad i i ‘OBSERVATIONS anp EXPERIMENTS ON THE ANIMALCULA OF INFUSIONS. * CHAPTER I. - WHETHER, ACCORDING TO A NEW THEORY OF GE. NERATION, ANIM.LCULA ARE PRODUCED BY A VE. GETATIVE POWER IN MATTER. INFUSIONS AND IN. FUSED SUBSTANCES EXPOSED TO HEAT. ! Noruine is more common with philofophers who have invented any theory, or given a new form to one already eftablifhed, and univerfally known, than to republifh it on fome other oc. cafion, corrected, improved, or uluftrated, with additional information. If we would review our difcoveries, if we would examine them profound. ly and with impartiality, we fhould in general find defeéts unnoticed before, which arife from Vou. I. A , the D ANIMALCULA OF INFUSIONS. Mae va the want of connettion’in fentiment, from the want of a neceflary and laudable perfpicuity, or becaufe they are difcordant wi ith more recent difcoveries. A certain vegetative power fome have conceiv- ed to refide in matter, appropriated to the forma- tion and regulation of org ranifed exiftence ; that by it are the numberlelfs combinations of the ani- mal machine effected ; the operation of nutrition and perfpiration, the variety of conftitution, the animal appetites and dimenfions of the human frame. By the fame means has it been explain- ed why a blind or a maimed perfon may have children vigorous and entire ; becaute the vege- tative power will reftore to chet the members defective in the parent. Not only has it been fuppofed to be deftined for the organization of matter in animated be- ings, vegetable ftate, and the vegetable again to an sattaalle that it acts on plants while living, and when dead regenerates them in new beings; thefe are the animalcula of infufions, which cannot ftrictly be called animals, but beings fimply vital. One proof as in fupport of this hypo- thefis, is derived from th. origin 0 animalcula. We are told they muft either come from fpecific feeds, or be produced by the vegetative power ; that but that it mich t change an animal to the - er ¥ I, ANIMALCULA OF INFUSIONS. 2 that the firft cannot take place, becaufe they are found in clofe veffels fubje&ed to the ation: of heat, equally as in open veffels, whereas the in- cluded germs, if there were any, ought not to furvive. Therefore, they mutt originate from the vegetative power alone. Nothing has been o- mitted to obtain favourable arguments for this opinion, and to give it that clearnefs, elegance, and fimplicity motft likely to gain converts. Nineteen veffels, containing infuied fubftances, were hermetically fealed, and kept an hour in boiling water. Being opened at a proper time, not afingle animalcula was to be feen Cope lo this experiment of mine, it was objected that the Jong continuance of heat had perhaps entirely deftroyed the vegetative power of the infufed fubftances, or materially injured the elaflicity of the air remaining included in the veflels ; thus, it was not fiearican if animalcula did not appear. To eftimate the weight of thefe objections, I conceived an experiment eppareaaly decifive ; which was, to make nineteen | infufions, and boil } fome of them a fhort time, others longer, and the reft very long. If it was founded, the num- ber of Witte would be lef according to the duration of boiling, if not, the number iid be alike in all cafes. 2. ° T tahla A = V eceiable w {1) Saggio di offervazioni microfeopiche, 4 ANIMALCULA OF INFUSIONS. 1, Vegetable feeds, being the moft fit for produc- ing animalcula, were preferred, to other fubftan- ces, and thofe that never failed to produce them though they had experienced the influence of heat. White kidney beans, vetches, buck-wheat, barley, maize, the feeds of mallows and beets were infufed ; and, that the experiment might be the more accurate; I endeavoured as much as poflible to take each fpecies of feed from the fame plant. As the yolk of an egg in macera- tion abounds with animalcula, one was alfo infuf- ed. Experiment has demonttrated, that the heat of boiling water is not always the fame, but greats er, if the atmofphere is heavier; and lefs, if lighter: therefore, water will acquire more heat at one time than another, which will be propor- tioned to the ftate of the atmofphere. In this, and my other experiments, the feven different kinds of feeds, and the yolk, were all boiled an equal time, that they might acquire the Jame de- gree of heat. Here the experiment was diverfi- fied, by boiling a certain quantity of each infufion halfan hour; another quantity, an hour; a third, an hour and a half; anda fourth, two hours. Thus, four clafles of infufion, and the egg, could be formed. The fame water, in which the feeds had boiled; was taken for the infufions, and what had’ boiled half an hour alone taken for the # z de ' : [. ANIMALCULA OF INFUSIONS. 5 the feeds that had boiled half an hour. The like proportions of time were preferved in the water for the other three clafles of infufions; that is, an hour, one and a half, and two hours. Each of the four claffes was marked with a different number, to avoid all hazard of confu- fion or error: and, becaufe an equal temperature was moft effential, all were depofited in the fame place. The veflels, containing she infufions, were not hermetically fealed, but loofely {topped with corks; the only object of this examination being to difeover, whether long protracted ebullition would prejudice or deftroy the property of infuf- ed fubftances in producing animalcula; if it did, there would be no difference whether the veflels were open or clofe. The examination of one, or of few drops, will often induce an obferver to fuppofe the infufion quite deferted, or very thinly mhabited, while the obfervation of many drops proves it to be otherwifé. I was not content with one drop on- ly, but uniformly took a confiderable number from each infufion. . The furface of infufions is generally covered with a gelatinous feum, thin at firft, and eafily broken, which, in proce(s of time, acquires con- fiftence:~ « Here; animalcula are always moft humerous, as may be feen by a method I have B3 conitantly + 6. ANIMALCULA OF INFUSIONS. é. conftantly practifed, examining with a magnifier a portion placed in a {trong light. Where the animalcula are minute, or rare, the thicknefs. of the infufion often prevents the obferver from diftineuifhing whether any are there or not. It is then neceflary to dilute the drops with water. Elfewhere it has been re- marked, that diftilled water was taken to make the infufions; common water might introduce fome latent animalcule (1). Inthe courfe of thefe obfervations and experiments, diftilled water, has alfo been employed for dilution, when required ; and, for greater fecurity, examined with a mag- nifier before being ufed. _ In particular cafes, the accidental concealment of a fmgle animalcule might vitiate the truth of the experiment., I conceive it my duty to mention precautions fo effential, and to put it in every individual’s power to judge not only of the experiments and obfervations themfelves, but of the mode of con- ducting them in matters io nice and important. On the 15 of September, I made thirty-two infufions ; and on the 23 examined them for the firft time. Animalcula were in all; but the number and. fpecies different in each. In the maize infufions, they were fmaller, and propor- tionally more rare, according to the duration of ~ bailing. From (1) Saggio o diflertazione citat. Cap. 4. 1f ANIMALCULA OF INFUSIONSé % From this it may feem, that although long continued heat had not prevented the production of animalcula, it had contributed to diminifh the number, or alter the kind. But with the reft of . the infufions it was otherwife: the kidney beans, vetches, barley, and mallow feeds, were in a bet- ter condition, after fuftaining the violent impref- fion of heat two hours, than thofe that had been expofed to it lefs. Let us enter on that detail which the fubject merits. In the infufion of kidney beans, boiled two hours, were three fpecies of animalcula; very large ; middle fized ; and very fmall. The fi- gure of the firft, aaa umbellated and attached to long filaments dragged along in their pro- gtefs; the fecond were cylindrical ; ;. and the third, globular. All three were incredibly nu- merous. In the infufion boiled two hours, were animal- eula of the largeft and fmalleft clafs, but few in number; ftill fewer, in that boiled an hour; and fewelt of all, in that boiled half an hour. The infufion of mallows, boiled two. hours, produced middle fized circular animalcula ; and fome very large, with the head extremity hooked. In two infufions, boiled an hour, and an hour and a half, the number and fpecies were the fame: and though they might be furpafied by thofe of the infufions boiled two aa {till they A a were 8 ‘ANIMALCULA OF INFUSIONS. T were-_much more numerous than in thofe boiled’ half an hour. we In vetches, boiled half an hour, was an im- ‘menfe number of femicircular bell-fhaped ani- malcula, all of confiderable fize, while in thofe boiled an hour and a-half,; they were. finall and rare. Some bell-fhaped animalcula might be feen- im-an infufion boiled an hour, but it gave the. eye pain to difcover a few, and thefe moft mintite,, when it had boiled only half an hour: Thofe in a barley infufion boiled two hours: were numerous beyond defcription, and large; part of an elliptic figure, others oblong (1). The infufions boiled an hour and a half had but a moderate number of animalcula very minute 5: and fome appeared when boiled half an hour. © There was no fixed rule with the remaining in- fufions.. In buck-wheat boiled an hour and a half were many more animalcula than in any other’ infufions of it. This alfo happened in the egg and beet feed boiled an hour; but it is to be re- marked, that fewer animaleula were in thefe two: infufions boiled half an hour than in any of the reft. Hitherto, the figure of thefe legions of animal- ) cula has been curiorily alluded to.. A circum- ftantial (1) Probably the author means different kinds of ellipfe. At the fame time, there are animalcula, though few, near- ly of an oblong figure. Moit of the defcriptions in all this ae ea ; Tra& are fo general, that it is difficult to afcertain the exact fpecies of animalcula.—TransLaror. Tt © ANIMALCULA oF INFUSIONS. 6 ftantial account is in my Differtations, and it will be fpoken of more at large in the courte of the Tract. ) Thus, it is clearly evident, that long boiling of {eed infufions does not prevent the production of animalcula; and, notwithftanding the maize does not feem to favour it, four infufions ftronely cor- roborate the fact. What is the caufe that infufions boiled leaft have feweft animalcula? I cannot think myfelf miftaker in afligning the following reafon. That animalcula fhould appear, it is neceffary that the macerating fubftances give fome indication of the diffolution of their parts; and, in proportion as diffolution advances, at leaft for a limited time, the number of animalcula will increafe. The uni- formity of this has been fhewn in another place, and would be confirmed, was it requifite, by fur- ther experiments and obfervations, in thefe new inquiries. Now, as feeds have boiled a fhorter time, fo are they lefs invefted and penetrated by the diffolving power of heat ; therefore, when fet apart to macerate, they are not fo foon decom- pofed as thofe longer boiled. ‘Thus, there is no occafion for furprife if fome infufions fwarm with: animalcula while others have very few: And this I do believe the reafon why, when two infu- fions are made at the fame time, one of unboil- ed, the other of boiled feeds, animalcula are fre- quently id ANIMALCULA OF INFUSIONS fj quently obferved much fooner in the latter thar in the former. A little boiling will not decompofé vegetable feeds, for decompofition is effected by flow and gradual maceration. Some days after thefe experiments, the number of animalcula always became greater; and towards the middle of O&ober increafed fo much, that each of the thirty-two infufions was equally fwarm- ing. The only difference was in fize, figure; and motion: I enjoyed this pleafing microfcopic feené uninterrupted until the 10 of November ; and it might have amufed me longer had I continued to examine the infufions. It ought not to be omitted, that experiments exaQtly fimilar were foon afterwards made with peafe, lentils, beans, and hemp feed. Except in the beans, the refult fo far correfponded, that a greater number of animalcula appeared in the in- fufions that had boiled moft. It is a fact eftablifhed by the univerfal concur- rence of philofophers, that, after water has come to the {tate of ebullition, it cannot acquire a greater degree of heat, however much the aCtion of the fire may be augmented, provided it can evaporate. ‘Therefore, when I fay the feeds boil- ed longeft have acquired greater heat, I mean it to be underftood in time and not intenfity, by fuppofing that the duration of boiling encreafed the / 3 ANIMALCULA OF INFUSIONS. if the intenfity of heat the feeds would be expofed to. Recourfe was had to another experiment to learn whether an encreafe of heat would obftrué the production of animalcula. ‘The eleven fpe- cies of feeds were flowly heated in a coffee roafter till they became pretty well roafted, and eleven infufions formed of them with water previoufly boiled as ufual. But this heat, fo much more intenfe, neither prevented the origin of animal- cula nor leflened the number. They were rare at firft; but about the middle of O&ober, that is, twenty days after making the infufions, the fluid was fo full as abfolutely to appear animat- ed. The conftancy of their appearing even here, excited my curiofity to augment the heat {till more. The feeds were burnt and ground the fame as we burn and grind coffee. Of the duft, which refembled foot, I made as many infufions as different kinds of feed: likewife, an infufion was made of the yolk of an egg, which by the thermometer had fuffered 279° of heat (1). What followed ? (1) The author ufed Reaumur’s thermometer in all his experiments. As Fahrenheit’s is the only thermometer ufed in this country, the degrees of heat are here reduced to his flandard, 2.25 of Fahrenheit being equal to 1° ef Reaumur. The fractional parts of the former are not given, both becaufe experiments can feldom be made with- in * 4 13 ANIMALCULA OF INFUSIONS. | i, followed? Animalcula equally appeared in thefe infufions, only a little more time elapfed before they became fo numerous, becaufe the weather was colder; and they uniformly inhabit infu- fions fooner or later according to the tempera- . ture of the atmofphere: Vegetable feeds were expofed to trials more fevere: they were expofed to the greateft heat that can be excited by common fires, or fire aug- mented by art: Burning coals, and the flame of the blow pipe, were the two agents exercifing their power on them. And, in the firft place, I kept them on an iron plate above burning coals until entirely confumed by the violence of the flames, and converted to a dry cinder, which was reduced to powder, and as many infufions form- ed as there were feeds. A cinder was alfo made by the blow pipe, which, befides exceffive aridi- ty, had acquired confiderable hardnefs. I muft acknowledge I did not in the leaft expeé to find animalcula in this new infufion. After viewing them once and again, hardly able to credit my eyes, | repeated the experiment twice. Some fuf- picion arofe that the animalcula might come from the water ufed rather than the burnt feeds; therefore, on repeating the expériment, the fame as in parts of a degree, or thermometers to agree exactly, and becaufe the. difference here, where there is any, never exceeds .25 of 1°.—T. 1, ANIMALCULA OF INFUSIONS. 13 as what formed the infufions was put in other veflels. Both times, however, they re-appeared in the burnt feeds, while not one was feen in the ‘water. Thefe fa&ts fully convinced me, that vegetable feeds never fail to produce animalcula, though expofed to any degree of heat; whence arifes a dire& conclufion, that the vegetative power is nox thing but the work of imagination; and if ne animalcula appear in veflels hermetically fealed and kept an hour in boiling water, their abfence mult proceed from fome other caufe. CHAP. II. WHETHER THE INFLUENCE OF HEAT DIMINISHES THE ELASTICITY OF AIR INCLUDED IN VESSELS HERMETICALLY SEALED; AND IF IT WOULD BE AN OBSTACLE TO THE PRODUCTION OF ANIMAL, CULA, Tus inquiry may be reduced to two heads: Kirft, By fubje&ting a given number of veflels hermetically fealed to heat fo regulated that ‘they might fuffer different degrees, and obferving if the production of animalcula is obftructed or altogether 4 ANIMALCULA OF INFUSIONS. I, altogether prevented, by increafing the heat. Se. condly, Whether the increments of heat prove the diminifhed elafticity of the air. For convenient examination of both, eleven vef. fels, containing eleven kinds of the fame vege- table feeds as before, were hermetically fealed. But, to proceed with due caution, it was eflential that the included air fhould undergo no fenfible rarefaction in fealing with the blow pipe, and not lofe its elafticity, which would affuredly happen if the veffels were fealed without any further pre- paration, by the flame furrounding and foftening the neck : for fuch powerful heat, after commu-- nicating from the neck to the belly, could not | but expel great part of the included air, whence the part remaining behind would become more or lefs rarefied, and more ox lefg elaftic accordingly. Indeed, when the hermetic feal is broken, after the veffel cools, a faint hiffing is almoft always heard, which proceeds from the air efcaping by the orifice: and that this is the fact is certain, by. applying the flame of a candle near the feal ; when broke, the flame is driven from the aper- ture, and fometimes actually extinguifhed. If the feal is broken when the veffel is inverted in wa- ter, the water fuddenly rifes above the level of what furrounds the veflel; a moft fatisfa€tory proof of the internal air being more rarefied than * the external. ‘Fo avoid this inconvenience, the neck 1, ANIMALCULA OF INFUSIONS. ig neck of the veffel was drawn out at the lamp al. moft to a capillary tube: the fmalleft part was then inftantaneoufly fealed, fo that the internal air could fuffer no alteration, as was evident from no hiffing being heard on breaking the veflel. After afcertaining that the included air was of the fame denfity as the atmofpherical, it was ne- ceflary, before expofing the veflels to heat, to in- veftigate, whether fimple inclufion of the feeds would obftruet the production of animalcula: Was it fo, it could be afcribed neither to heat nor air, but the clofenefs of the veflels alone. Other experiments had rendered me cautious here(1). They had taught me, 1. Infufion ani- malcula are not produced in veflels hermetically fealed unlefs the veflels are capacious; 2. They are not always produced; 3. ‘hey are never fo numerous as in open veflels. I now felt the ne- ceflity of fuch circumfpection, and ‘although it was ufled, two fubftances, kidney beans and peafe, ceafed to produce animalcula. ‘The other nine feeds produced a moderate number. To thefe nine only, I confined mylelf, and fubjected each to heat in the following manner. Nine veffels, hermetically fealed, containing feeds, were im- merfed in boiling water half a minute; other nine, a minute; nine more, a minute and a half; and nine, two minutes. Thus I had thirty-fix, in- fufions, (i) Differt. Cap. ro, * 16 ANIMALCULA OF INFUSIONS. L fufions, the feeds in which were expofed to the heat of boiling water. To difcover the proper period for examining the fealed veflels, fimilar infufions were at the fame time made in open veffels; and, when animalcula abounded there, thofe fealed up were vifited. In eleven days, the nine open infufions being full of animalcula, it feemed fit to examine the others. On breaking the” \ firft hermetic feal, 2 faint hiffing was heard, not unlike that mentioned above. Then it did oc- cur to me that heat had truly injured the elafti- city of the internal air, and excited me to ob- ferve, with the utmoft attention, what happened. on breaking the feal. The hiffing was. obvious. in all; but I foon difcovered it arofe from an op- pofite caufe, namely, encreafed elafticity of the air. In the firft place, the flame of a candle was driven from the orifice; fecondly, on juft touch- ing the fealed part with a file, it twice fprung more than.a {pan from the veflel; in the third place, on making the infufion flow towards the feal, and then breaking it, the infufion .violently fpouted out; fourthly, the feal being broken - under water, inftead of ruining into the veflel, the water was forced away. Reflecting on the nature of macerating fubftances, I faw it could not be otherwife. Vegetable feeds are well known to contain a great quantity of air. Dur- ing i. ANIMALCULA OF INFUSIONS. 17 ing their diffolution by heat it muft be extricated, and in this way render the portion included more . elaftic. I do not deny, however, that this encreaf- ed elafticity may partly arife from an elaftic fluid, difcovered in vegetables, of a nature different from the atmofpherical fluid. To return to my microfcopic examination of the fealed infufions. It gave me great furprife to fee heat, fo very far inferior to that mentioned in the preceding chapter, had- obftructed the origin of our animalcula. Some infufions were an abfolute defart, and others reduced to fuch poverty as only to afford fo many wandering animalcula like points, and hardly perceptible(1). Let the reader figure two lakes ; in one, are fithes of every fize, from a whale down to the fmalleft; while in the. other are a few mi- nute fifhes, not larger than ants, and he will have-a fenfible idea of the animals appearing in the open infufions and thofe that appeared in the clofe. I was particularly furprifed how the heat of half a minute had been as injurious as the heat of two minutes. ‘Thofe inexpreflibly Vou. I. B minute (t) Monas Termo. Murine, Animalcula Infuforia, p. 1. Hauniae, 1786.—This is a fyftematic-work on the animal- cula of infufions, where the indefatigable author has def- eribed 378 {pecies of thefe fingular beings. ‘The reader will find a number of fynonyms, prabbdice — defcrip- tion, if the animalecula has come under the view of = AVE authors.—T. diy for | z Lis R ‘ a@ Wes i8 ANIMALCULA OF INFUSIONS. I, minute animalcula were produced from beans, vetches, buck-wheat, mallows, maize, and len- tils. Whatever attention was beftowed on the other three infufions, I could never difcern the leaft indication of animation. From this feries of experiments I concluded, that the heat of boiling water half a minute was fatal to large, middle fized, and finall animalcu- la, which, to adopt the energetic exprefhion of my illuftrious friend M. Bonnet, I fhall term ani- — malcula of the higher clafs ; while the fame heat, protracted two minutes, did not affect the infi- nitely minute animalcula, which I fhall term the lower cla/s. Here two problems occurred : Whe- ther the continuance of boiling longer than two minutes would prevent the origin of the lower clafs; or, if diminifhing the boiling lefs than half a minute, would admit the exiftence of the high- er clafs. As no two problems could be more - important, I endeavoured to folve them in the following manner. I began with the firft ; and, ufing the he already obferved, kept veflels with fix kinds of feeds, producing the lower clafs of animalcula, in boiling water, fome two minutes and a half, three minutes, three and a half, and four minutes. The hermetical feal of twenty four veflels was broken at a proper time ; though the higher clafs of anjmalcula was wanting, it was not fo with the i. ANIMALCULA OF INFUSIONS. 19 the lower; fome were in all theinfufions. In general, the hifling was heard on breaking the feals, which proceeded from the violent efforts of the air, rendered more elaftic, to efcape, as the proofs already given convinced me, and an addi- tional one occurred, than which nothing could be more decifive. A fmall barometer was includ- ed in a receiver full of common air; whenever the neck of a fealed veflel introduced by the top was broke, the mercury rofe in the barometer. To avoid redundancy, | may now remark, that condenfation of the internal air almoft uniformly -manifefted itfelf in the other experiment with heat yet to be narrated. Veflels were immerfed feven minutes in | boiling water ; animalcula of the lower clafs appeared in all fix ; and they conftantly originated though the infufions remained twelve minutes in boling ‘water. Perhaps it may be imagined that fome optical illufion deceived me; that I was induced to fup- pofe the lower clafs.of animalcula what arofe on- ly from the particles of the infufed fubftances. That it might be the confequence of decompofi- won by gradual fermentation, or by their lubrici- ty occafioning locomotion on the leaft fhock or agitation; or of an active and yolatile {pirit penetrating and putting them in motion; from a great evaporation, or one lefs copious; from B. 2 2 40 ANIMALCULA OF INFUSIONS. rt a powerful attraction or repulfion, by which the particles of the fubftances were forcibly attracted or repelled, or from any other accidental caufe - deceiving the eye. But in the fame manner as thefe, and fo many other fallacious appearances, may impofe on~him who is only beginning the dificult ‘art of experiment and obfervation, fo can they be properly appreciated by one well ac- cuftomed to microfcopes, and who has made the hiftory of thefe infinitely minute beings his long and particular ftudy. Notwithitanding the lower orders of animal- cula are incomparably fmaller than the others, . they are not fo very minute as not to differ in fi- gure and fize. ButI fhall not tire the reader with defcriptions. I would willingly have protraéted the heat by continuing the immerfion longer in boiling wa- ter, but the nature of the glafs prevented it ; for, after being a few minutes immerfed, all the vel- fels burft in pieces, and of a fuflicient number for my experiments I am fure two-thirds were loft. Therefore it became neceflary to procure _ elafs that would fuftain heat better; which was effected by putting only a {mall quantity of wa- ter in the veflels with celibene? Omitting this precaution, I was certain to fee them fly in pieces. It is needlefs to defcend to minute de- tails: the refult of experiment proved, that boil- ing \ t. | ANIMALCULA OF INFUSIONS. 21 ing half an hour did not prevent the origin of ‘the lower animalcula. Boiling three quarters, or a little lefs, rendered the whole infufions fterile. We know the heat of boiling water is about 212°. The infufions had evidently acquired this degree at leaft, from their ebullition, while the furrounding water boiled. I fay at leaft, for philofophers know, that water boiled in a clofe veffel acquires more heat than boiled in an open one. The firft problem being folved, which was to afcertain how much longer than two minutes in- fufions muft boil to obftruét the production of the lower animalcula. The fecond, which was the inverfe of the firft, remained fer folution, how much within half a minute, boiling would admit the origin of the higher clafs: A fecond watch was ufed; and the veffels were immerfed a cer- tain number of feconds, beginning with twenty- nine. Ina word, boiling fora fingle fecond pre- vented the appearance of the higher clafs. Thus Thad to take a lefs degree of heat, as 209°, 207°, 205°, 203°, until arriving at that which did not obftrué their exiftence. To be abfolute- ly fure the heat had time to penetrate the infufions, the water was gradually warmed, till attaiing the requifite degree, which was in- dicated by a {mall thermometer alfo immerfed. Bes But , 22 ANIMALCULA OF INFUSIONS. ft. But to recede by fuch fmall differences would lave been extremely tedious and troublefome ; and receding by great intervals, as for example, from 212° to 167°, 122°, might produce inaccu= racy, and admit that animalcula had appeared, not only at that degree, but at one much infe- rior, therefore I thought of adopting a mean temperature, which would both diminifh the la- bour, arid liberate me from the imputation of an unexact obferver. ‘The reduction proceeded by 11°, defcending from 200° to 189°, 178°, 16795 whence I had four clafles of experiments tcorref- ponding with the numbers:200, 189, 178, 167% Each clafs had nine infufions of the feeds before . named, which made’ thirty-fix veffels, whofe feals were broken, when the time neceffary for producing animalcala had elapfed: but not a fingle animalcule was in any one of the thirty-fix veflels. Whence I concluded, that'none of the © higher claffes could appear at 167°, which is 45° lefs than the heat of boiling water. Continuing to defcend by 11° from 156°, I came to 111° ; whence I had five claffes of infuftons, and forty five veflels. My furprife has already been expreffed at fee: ing fuch abundance of. animalcula of every def- cription, in fub{tances openly infufed, after ex- pofure to the violent flame of the blow-pipe: but it gave me no lefs aftonifhment not ‘to find - a fingle. ] J; ANIMALCULA OF INFUSIONS. 23 a fingle one of the higher clafs in infufions her- metically fealed; though they had fuffered only the moderate heat of 111°. This was done in the middle of July ; and the thermometer in the fhade ftood at 88°. Eighteen veflels were put to the teft: nine fuffered 99°, and nine 88°. No animalcula of the higher clafs were produced at 99° ; but the whole nine infufions produced them at 88°. Animalcula, the fame in number and fpecies, were in each veilel, as in the clofe infufions not fubjected to heat. From this fact, it was eafily difcovered, that the degree of heat fatal to thefe animals was between 99° and 88°; and I found it tobe 95°: at 93°, a few of the higher clafs appeared ; at 95°, only thofe of the lower. The method of opening the infufions has been, defcribed towards the beginning of this chapter. When clofe infufions were made, I alfo formed open ones: and both being put in the fame place, to have an equal temperature, when the open infufions abounded with all forts of animal- cula, 1 examined the elofe. Such a plan always feemed the beft ; neverthelefs, if difappointed of feeing animalcula, I changed it oftener than once: fometimes the veffels were opened fooner, fometimes later ; and though trequently delayed very long, the fact was uniform. In fhort, I re- main under the moft abfolute conviction, that B 4 the 24 ANIMALCULA OF INFUSIONS. I. the non-exiftence of thefe animalcula does not depend on the duration of time, but entirely on the action of the heat to which infufions have been expofed. Before terminating the experiments before us,. and making the reflections which they merit, let a word be faid, in paling, of the death of ani- ‘malcula, after fpeaking fo largely of their birth, | We. have feen the lower clafs originate, in clofe _weffels, at 212°; while the higher {carcely can at 93°. . It would therefore appear, that, on ex- pofing both to heat, the lower clafs fhould refift it much better than the higher: however, the fame degreé that is fatal to the one, is fatal to- the other; and both conftantly die at. 106°, or,: at moit,.108 °. Two important confequences flow from thefe: experiments: Firft, The efficacy of heat in ren-- dering clofe infufions. barren of an infinity, of animated beings. In open infufions, are an in- credible number and variety ; while in the clofe, fubje&ted to the aCtion of fire, one feeks in vain for an animal which he can call even the fmall- eft in fize. We cannot affirm, that fimple inclu- fion occafions fuch devaftation, fince, in other’ cafes, it only diminifhes the number : therefore, . we muft conclude, that heat truly does it. But how can it operate? Can we think it is by rendering infufed fubflances unfit for producing: animalcula & fh. ANIMALCULA OF INFUSIONS. 25 animalcula? The infufficiency of fuch a fuppo- fition has already been feen. Neither can heat impair the elafticity of the internal air : becaufe, from the precautions taken, there was. not. the _ leaft difference between the {tate of the internal air and the external; and attending to what hap- pened on opening the veflels, fo far from that within being lefs elaftic, it is even more fo than the other. It is impoflible to conceive the en- creafed elafticity is prejudicial to the origin of our animalcula, as I have feen them where the air was condenfed twice or three times more than. its natural ftate.. ‘The conclufion will then fub- fift, that when the higher clafs does not. appear, it is becaufe heat has vitiated or injured the pro- ductive principle. - The force of this conclufion will afterwards be better comprehended. ‘The fecond confequence is the inverfe of the firft,. and refpects the conftancy or rather certainty of animalcula appearing in boiled clofe infufions. And this refult is no more favourable to the rea- fon affigned for none originating in infufions: boiled an hour, becaufe too great heat had def- troyed the vegetative power, or impaired the elafticity of the air; nor with the time I ought to expofe infafions to heat, and ftill fee animal- cula, which has been prefcribed to be as much as. will deltroy the eggs of the filk-worm-moth, that 1S, 135° , or 128°, or 140°, the fame as we thall {aon 26 ANIMALCULA OF INFUSIONS. I, foon fee that renders their eggs unfit for exclu- fion. But I have not only found the loweft ani- malcula at that degree, but at 212° continued fully half an hour. Thefe are the facts I have deemed it neceflary to collect for eftimating the weight of the two objections to my experiment: and we readily fee how difcordant they are. If, in the heat experi- ment mentioned in my Differtation, I found no motive inducing me to admit an tmagined vege-. tative power, I have now the ftrongeft reaforis for rejecting it as inconfiftent and chimerical. And as i could not then conceal my propenfity to believe, that infufion animalcula originated from germs, neither do I hefitate here to fay, propenfity has become perfect conviction(1). If the animalcula, in clofe veffels fubjected to heat, do not originate from the vegetative power, I do not (1) In the ceurfe of this work there are many allufions to germs. The great difpute concerning the generation of animated beings feems to refolve into the queftion, Whether there is a preorganized principle continually m- volved in another preorganized principle, and fo on, by fucceflive involutions, from all eternity, and this, by the concurrence of peculiar circumftances, expanding into the complete animal; or if itis more probable, that by the intercourfe of the fexes, or otherwife, fome change or creation is effected, which gives birth to a new anima! or a wanting part: Both hypothefis are attended with infinite dificulty.—T. t. ANIMALCULA OF INFUSIONS: a4 sy not fee how we can afcribe their origin to any thing but eggs, feeds, or preorganized corpufcu- fa, which we underftand and diftinguith by the generic name of germs. ‘That fuch is the real origin of animalcula will be direétly proved, in the courfe of this Tract, by incontrovertible facts. An objection, it is true, here prefents itfelf, which impartiality will not permit me to conceal. Speaking of germs that develope into the loweft order of animalcula, we muft admit, that thefe germs have refifted the heat of boiling water, and that for three quarters of an hour; for it cannot be fuppofed they have paffed from the air and infinuated themfelves through the pores of glafs, after cooling of the veffels. Such fuppo- fitions, if not impoffible, are certainly very diffi- cult to be comprehended. However this fhould rather be called a doubt or difficulty than a real objection ; fince, when well weighed, it may bé reduced to the confideration, whether we can conceive germs of animals in nature, whofe ex- treme fubtility permits their paflage through glafs, or whofe conftitution allows them to with{tand the heat of boiling water. As to the firft hypo- thefis, though I do not find it abfolutely repug- nant, becaufe we know there’dre animals fo very minute that their exiftence never would have been credited but for the microfcope, I cannot admit it for the following reafons. In the Arf place,. 28 ANIMALCULA OF INFUSIONS. 1; place, becaufe the fize of germs is proportioned to the fize of animalcula, as I have feen in more than one {pecies ; and; on the other hand, the lower animalcula; confidered in themfelves, be- ing of fome fenfible fize, fo fhould their germs be of fome fenfible fize,; fuch, at leaft, as prevents them from penetrating glafs; particularly when we know, that other corpufcula apparently more minute, as the particles of air and water, of the moft acute and penetrating odour, cannot do it (1). In the fecond place, thefe animalcula are produced not only in glafs, but even in metal veflels fealed with metal, immerfed above half an hour in boiling water, as I have twice had_occa- — fion to experience, notwithftanding the greater narrownefs of the porés, or more irregular and tortuous pofition, made it impoilible to conceive - the germs would penetrate the fides of the metal. Finally, Was the hypothefis true, animalcula of the lower clafs fhould originate equally well, whatever is the duration of boiling ; for, in both cafes, the paflage of the germs through the fides: of the veffel fhould be equally fuccefsful. On the contrary, not one appears after boiling three quarters of an hour. Thus we are led to afcribe their origin to in- cluded germs, which for a imited time can refift the (1) Academ. del Cim. i, ANIMALCULA OF INFUSIONS, 29 the influence of heat, but at length yield under it. As the higher clafs does not originate unlefs at a much more moderate degree of heat, there is a neceflary inference, that the germs of this clafs are much fooner affected than thofe of the lower ; whence we mutt conclude, that the amaz- ing multitude of animalcula in the infufions of open veffels expofed to boiling heat, and the in- tenfe flame of the blow pipe, do not appear be- caufe their germs have rejifted fo great a degree of heat, but becaufe other germs have come to the infufions afiecr ceffation of the heat. But is there any proof, or any forcible argu- ment, to remove or leffea our natural repugnance to fuppofe that germs of the lower .animalcula can refift the heat of boiling water? To fpeak of the germs or eggs of animals known to us, are there none of this nature? Undoubtedly, as far as our knowledge extends, we are unacquainted with any of that defcription. Something has been faid on the fubject in the ninth chapter of my Differtation, demonftrating how the eggs of va- rious infects, as well as thofe of birds, perifh at a _ degree of heat confiderably lefs than that of boil- ing water. It is further fhown, that this heat in- jures the feeds of plants, even thofe with the hardeft fhell. A greater number of feeds and eggs, indeed, might have been fubjected to experiment : and fome may be found capable of ftanding the trial. $0 | ANIMALCULA OF INFUSIONS. . ° L trial. With regard to feeds, hope fhould not be abandoned from reading in Duhamel, that he fucceeded in the germination of wheat which had fuffered 234° in a ftove ; and it is very probable this feed is not unique. So many analogies. ex- iting between feeds and eggs, I indulged the hope of finding fomething fimilar in the lat- ter. Thefe facts were fufficient inducements to make new experiments on feeds and eggs, to which I was additionaily incited by the moft fin- gular phenomenon of the loweft animalcula ori- ginating in boiled infufions: and, in cafe eggs and feeds fhould not withftand the heat of boil- yng water, it would ftill be ufeful to afcertain what they could fupport, by pafling through va- rious degrees to that which was fatal to them. But there was one particular inquiry not to be omitted, namely, whether animals and _ plants were more eafily deftroyed than their eggs and feeds, and in what proportion, the fame as ani- malcula of the loweft clafs can fupport heat lefs than their germs. As all fuch inveftigations would greatly elucidate the prefent refearches, I endeavoured to realize them by experiments, which will afford matter for the fubfequent chap- ter. CHAP, T. | —s ANIMALCULA OF INFUSIONS. 2% CHAP. III, EGGS AND ANIMALS, SEEDS AND PLANTS, EXPOSED TO DIFFERENT DEGREES OF HEAT. In the month of May, I fifhed up the eggs of frogs, which had a few hours before been depo- fited in the water of ditches. The quantity was divided into equal portions, and each expofed to a different intenfity of heat, in this manner. The eggs were completely immerfed in water, where Thad put the ball of a thermometer. The veffel was then placed on a flow fire; and, when the thermometer had attained the requifite height, the eggs were taken out, and each portion put in a veflel of cold water. I had ten veffels, becaufe there were ten portions of eggs that had experi- enced different degrees of heat, as 111°, 122°, Pag s Ta4c, 1555, 107... 1705" Leg. 200". 212°. | The eggs that fuffered 111°, 122°, 133°, pro- duced young, but with fome difference. Almoft all thofe at 111° were fertile ; fewer produced at 122°, and the number extremely {mall at 133°. The whole that were expofed to greater heat became corrupted, $2 . ANIMALCULA OF INFUSIONS. T. sd corrupted. The heat neither accelerated nor re- tarded the exclufion of the eggs, for tadpoles were . hatched in the fame time as in thofe not expofed, which had been referved for the purpofe of com- parifon. ~ Having afcertained the heat which the eggs of frogs could fuffer without injury to the tadpoles, I had to examine what heat the tadpoles produc- ed by them could bear; however, they were unable to refift as much, for all died at 111°. Thefe experiments were repeated on adult frogs. Although I had feveral fpecies, I prefer- red thofe that had produced the eggs. They in- habited the ditches of plains, were rather {mall in fize, and greenifh on the back. Being put on the fire, they had all liberty in the water; they could fwim at pleafure, and come to the furface to refpire: but a covering prevented them from efcaping. The whole perifhed at nearly about111°. I know there are ‘frogs that live in warm fprings, though the heat is greater than 111°. Thus, the illuftrious Cocchi relates, they are not injured in the warm baths of Pifa, where it is 111° by Fah- renheit, which correfponds with 37° of Reaumur’s thermometer (1). But we muft either fay they are of a different fpecies, or, beimg long accuf- —tomed “ (1) There feems to be fome error here: 37° of Reau- miur’s thermometer correfponds with 115° of Fahrenheit. ¥ oe I ; t. ANIMALCULA OF INFUSIONS. 33. tomed to that degree, fuffer no injury, though at firft it would have been fatal to them. And we know, that men who can hardly endure the va- pour bath fix minutes, and are covered with profufe perfpiration, can, in procefs of time, re- majn fifteen minutes without any fen{ible incon- ‘venience (1). we AG 4 Both man and animals can bear an incredible de- ine ‘of heat without perifhing, and even without any fenfible injury. Not that the living body will become heated to ahigh degree; it always preferves a tempera- ture near what it fhould have ina natural ftate. In a- memoir on this fubject, it is faid that a girl fupported 284°, in an oven without inconvenience. Thofe ferving. the oven bore 257° a quarter of an hour, and perhaps could have endured 212° half an hour. Trzzer fur les ‘chaleurs auquels les hommes font capables de reffler. Mem. del’ Acad. Roy. 1764. Several perfons bore a room heat- ed to 198°. 2109. 211°. The fame perfons could juft bear cooling fpirits at 130°, cooling oil at 129°, and cooling quickfilver at 117%. ‘They could not fuffer the heat of water at 125°; Philofophical Tranfadctions, 1775, Pp. 117s 120. Different perfons at Liverpool bore the heat of an apartment at 224°; and Sir Charles Blagden Doe one at 260°. Philof. Tranfac. A dog has been in the heat of 236° without inconve- nience; and a fpecies of tenia has been found alive in a boiled catp. In Ruffia, the vapour bath is faid by Storck to be generally 133°. according to D’Auteroche 167°: and Acerbi obferves, that thofe in Finland are from 158° to 167°.---T. ‘MO. Io ¢ I 34 ANIMALCULA OF INFUSIONS. - ee I could have wifhed, when my experiments were made on other animals, to have alfo made them on their eggs; but it was not always as convenient for me to procure the latter. Thus when, at one time, I had abundance of larvee. of mufkitoes, water fleas (1), rat-tail worms (2), and other aquatic infects, I never could fucceed in finding the eggs whence they originated. However, it did not appear that my labour would be loft in making experiments on the animals. The nymphs and larve of mufkitoes ( 3) died at 111° ; rat-tail worms and water fleas, at 106° ; water newts and leeches died at 111°; the eels of vinegar, at 113°. In my experiments on filk-worms, the caterpil- lars of elm butterflies, and the worms of the large flefh “fly, I was more fuccefsful, as I had both the animals and theireggs. Until 93°, filk- worms did not appear affected ; at 95°, and par- ticularly (1) No name is*more incorredly applied in general _ than «water fea; almoft every fmall aquatic animal, even fquille and gyrini, have been fo defigned. It is moft likely the author means the mosculi of Linneus. There is a complete fyftematic hiftory of thefe, and many other mi- nute aga: animals, by Muller, Extomofiraca Jeu Infecta Teftacea, 1785, 4to.—T. (2) Sate fo denominates certain white worms from the refemblance of their tail to a rat’s. (3) It is uncertain whether the author may not mean tipulae—T, * I, ANIMALCULA oF INFUSIONS. 35 ticularly at 97°, they became reftlefs ; at 99°, they ceafed to move; and at 108°, all had perifhed. The eggs producing thefe animals long refifted the influence of heat : at 88°, they produced the greateft poflible number of worms; at og”, many, but fewer than before; and the number always diminifhed as the heat encreafed : at iB Oe not one was fertile. -The eggs and caterpillars of the elm butterfly perfeétly correfponded with the filk-worms. It would be fuperfluous to fay more of them ; and I pafs to my experiments on the largefly. i | The fpecies was that which depofits the ego's on ficfh either putrid or tending to putrefy. Until 124°, a great many produced worms ; at 135° and 138°, very few; and all were fterile at 140°. The larvae of thefe eggs, at 88°, began to be reftlefs, and endeavoured to elcape : their agitation encreafed at the fubfequent degrees ; _ and at 108° all had perithed. Full eTown worms of the fame kind died at 108° alfo ; Changed to nymphs and files: the latter bore the heat worft of all; 99° degrees killed them. Flies came from nymphs at 104° and 106°; but none at 111°: having opened them, I found the heat had entirely dried them up. And this much being faid with refpe& to ani. mals, and their eggs, éxpofed to different inten- ; C 2 fities 36 ANIMALCULA ‘OF INFUSIONS. 3 fities of heat ; let us next narrate what happened to plants, and their feeds, in a fimilar fituation. - The feeds I ufed were grey peafe, lentils, wheat, lintfeed, and trefoil: each, as ufual, was expofed to a different degree, 167°, 178°, 189°, 201°, 212°, and then fown in a fmall ditn@ fpace of earth, fo prepared that each fpace might contain an equal number of feeds. Their germination was not injured by 167° ; 178° began to be prejudicial; very few fucceed- ed: at 189°, there were no more than eleven plants of trefoil, and only ten at 201° : of thofe expofed to 212°, only three germinated. Thus none of the feeds but trefoil could fuftain the heat of boiling water. The five feeds had been fubjected to heat by means of a fand-bed. In a fecond experiment, they were kept in water that was gradually heat- ed, till as hot as required, in the fame manner as before with feeds and eggs. Heat operated more’ powerfully on them here: at.167°, peafe and trefoil germinated pientifully ; but very little lintfeed, lentils, or wheat: at 189°, were only. feven ftalks of trefoil; and at 212° none. My cuniofity being fatisied with regard to feeds, I had {till to fatisfy it concerning the plants {prung from them. Growing plants, thirteen days old, were fubjected to 167°, 178°, 189° 201°, 212°, dipping the roots in water gradually warm- ed, ia ANIMALCULA OF INFUSIONS. 37 ed. Though immediately replanted in moiftened earth, all died. As 167° was too powerful for thefe young plants, the heat was reduced to 156° and 144° ; and this was not prejudicial to them, for the whole grew when replanted. I had already fubjected feeds to the influence of heat; but did not then think of doing the fame to their plants. The feeds were beans, barley, white and black kidney beans, maize, vetches, parfley, {pinage, turnips, beets, radithes, and mallows. They were heated to 167°, in fand, after the manner above defcribed ; and all germinated. At 178°, fome began to perifh; at 189° and 201°, very few fucceeded sirand: Jat 212°, only one plant of kidney beans. The ex- periment was repeated at 201° and 212°, on all the feeds, but not one germinated. _ My firft experiment having proved, that trefoil had refifted heat better than the reft, it occurred to me, that, it being the fmalleft feed, the fize might perhaps concur towards the caufe. Whe- ther more heat could be fuftained as the feeds diminifhed, could have been afcertained by intti- tuting a feries of experiments on a given number of vegetable feeds gradually decreafing in fize, But beans, and kidney beans, which are incom- parably larger than trefoil feeds, had fupported heat as well: and this induced me to abandon the idea, and {pare myfelf ufelefs trouble. C3 Ik 35 ANIMALCULA OF INFUSIONS. I. It may be proper here to recur to the feeds compofing feveral infufions, mentioned before, éxpofed to the heat of boiling water in veflels hermetically fealed. Two minutes immerfion admitted of full germination, but it ceafed if the heat continued longer: and the like happened in open veflels, only, thefe could fearcely bear two minutes, and the others could bear a little more. At firft fight, the experiments before us feem difcordant with the former, indicating the vege- tative faculty is loft when feeds in water are ex- pofed to 212°, or the heat of boiling water. By attending to the different modes of condudting the experiments, all inconfiftency difappears. In the former feries, the water was heated till begin- ning to boil; here, on the contrary, that im which either the fealed or open veffels were 1m- merfed two minutes, did not give the leaft fign of ebullition, and the included water would have required at leaft four or five minutes longer for it; that the feeds vegetated is not furprifing, while thofe named before did not, fince the one fuffered more heat than the other. Such have been my experiments on animals and their eggs, and on feeds and their plants ; which, although not very numerous, feem to bring cer- tain laws of nature in view, whence we derive fome elucidation of this fubject. We colleé, in the firft place, that the eggs of the animals ex- , é. amined. f. _ ANIMALCULA OF INFUSIONS: 39 amined were more able to withftand heat than the animals themfelves. Tadpoles and frogs died at 111°, while their eggs became fterile at 133°; and fome even not fo foon. Silk worms and the caterpillars of the elm butterfly died at 108°: their eggs did not produce at 133°. Large fleth flies perifhed at 99°, their nymphs at 111°, their larva at 105°, and eggs at 140°. Secondly, There is much the fame relation between plants arid feeds as between animals and eggs. Some, as trefoil, beans, and kidney beans, are fertile, after Hcwines been expofed to 212°, or the heat of boiling water, while their plants cannot fup- port 167°. Thirdly, The feeds of plants are more adapted for refifting the violence of heat than the . eggs of animals. All the feeds my experiments were made on by dry heating germinated, though they had fuffered 167°, and fome 212°, but no egg was hatched after 144°. Laftly, It is to be re- _marked, that heat is more noxious when acting along with water. None of the feeds in water at 212° afterwards germinated. lam very far from pretendi Ing to give reafons for all thefe refults. I feel the difhculty of the enterprife, and at moft fhall only hazard fome con- jectural explanations, allowing whatever weight they. merit, and permitting every one to think as he judges beft. It may not be difficult, if we take the firft appearance only, to comprehend why © 4 plants 40 ANIMALCULA OF INFUSIONS. 1. plants and animals do:not fuftain heat fo well as. feeds and eggs ; and it would feem, becaufe they receive the immediate impreffions,\ which is not fo when included in the feed or egg. But was the difference.only a few degrees, which the ani- mal: could fuftain in the egg and out of it, and the fame will apply to plants, this reafon might — be good, however, when that difference reaches 22°, nay 31° and more, who does not perceive the infufficiency of it ? Befides, we fhould necefla- rily have to.admit, that the integuments of eggs: which in many infects are but as points in mat- ter, would-be able to protect them againft. 22 or 31 additional degrees of heat,. which is: very: im- probable,. when we confider its extreme facility and aétivity in penetrating fubftances fo per vious. Neither do I thmk the minutenefs. of the germ in the egg a fatisfaCtory reafon why it thould be lefs fenfible of the impreflions of heat’; for, however {mall it may be, the particles of heat 2re incomparably fmaller, and they will there- fore inveft and penetrate it on all fides, the fame ° * . as they inveft and penetrate. it when developed. A complete refutation of this imaginary reafoning is in the ninth chaper of my. Differtation. Before we are able to conceive why an animal inthe egg is not fo eafily deftroyed by heat as after it is produced, we muft take an accurate view of what conftitutes life in both thefe fitua- tions.. ee L ANIMALCULA OF INFUSIONS. at tions. But, if the life of animals in exiftence js fo little known, notwithftanding all the efforts of modern phyfiology, much more obfcure mutt be the life of an animal concealed or concentrated in an egg. Certainly we may conclude, that the life of an animal in the egg is moft feeble com- pared with that of the animal produced. Dur- ing the firft hours of incubation, the animation of the chicken is indicated only by the beating of the heart. Life before this is {till more feeble: it is a leffer life, doubtlefs fuch as that in the germs of infects eggs previous to their having experienced’ the degree of heat neceflary for ex- clufion. Can this moft faint and feeble anima- tion be any reafon why it may endure more heat than after it is developed? Certain it is, that animals, when in 2 ftate of very feeble life, which hardly merits the name of animation, do refift external injuries with much greater impunity than when moft vivacious (1). (Thus, if we cut off \ the (1) This certainly depends very much. on the nature of the injury to which the germ or animal is expofed, for the imperceptible agency of particular fubftances, whofe nature we are little acquainted with, are noxious. ‘Thus Michelotti inclofed.a number of eggs in glafs veffels, fome of which admitted the rays of light, and others excluded them. Few or none in the former were hatched; whence, from a feries of experiments, he concludes that light is prejudicial ‘to the developement of all the germs of ani: mals, and the fame with refpect to vegetable germs.—T., 42 — \ANIMALGULA OF INFUSIONS. f, the head of a frog, toad, lizard, fnake, or viper, or take out the heart, or deprive them of fome member during winter, while torpid with thé cold, and.apparently more dead than alive, they furvive the ‘operation much longer than if they undergo it in fummer, when in the vigour of life. I have often admired this faét; and that infects immerfed in water in winter live longer than if immerfed in fummer. There is no doubt that. the life of plants is weaker while included in feeds than after they are produced ; and why may not this leffer life, as with the germ of an animal in the egg, render them lefs fenfible of the impreffion of heat? In winter, when plants are furely lefs alive than in other feafons, are they not lefs liable to perifh on being rooted up, wounded or mutilated, than on doing this during fummer ? I fhould not fuppofe that the reafon why eggs 3 are more unfit for fupporting heat than feeds is from the greater foftnefs of the former, becaufe there are feeds not nearly fo hard as the thell of an egg, and ftill capable of fupporting the heat of boiling water, as trefoil feeds, but from fluids . being more abundant in the egg, by means of which heat has more influence in deftroying the germ. Experiment renders it undoubted, that the fluids of eggs, and confequently of their germs, are more abundant than in vegetable feeds. That ANIMALCULA OW INFUSIONS. 43 That this’ excefs of fluid contributes to deftroy the germ more readily, appears to happen from the heat expanding the fluids, and putting them in motion; thus they muft violently ftnke againft the very fubtile filaments of the germs, and occa- fion their rupture and deftru@tion. This we have actually witneffed in the feeds that become fterile with lefs heat in water than if dry. For a fimilar reafon does a piece of ice melt fooner in warm water than in air of equal temperature. But let us leave thefe intricate refearches, which ate in fome meafure foreign to our in- quiries, and compare the refults concerning feeds and eggs with thofe concerning infufion animal- cula. If we mean to aflume a ftandard of the heat which the germs of the loweft clafs of ani- maleula can fupport, from that which eggs with- ftand, we cannot be divefted of a natural repug- nance to fuppofe them capable of enduring boil- ing water, when eggs are incapable of doing near fo much. If, inftead of comparing the germs with eggs, we compare them with vegetable feeds, eur repugnance is wonderfully diminifhed ; for, befides Duhamel’s wheat, we have feen other feeds, as trefoil, beans, and kidney beans, refift heat as great. However, in purfuing this analo- gy, we incline more to compare them with the germs of eges than feeds. At the fame time, there are eggs that may moft properly be com, . pared ey "KNIMALCULA OF INFUSIONS; fe pared to feeds, fince, like them, after becoming dry, and» remaining tong in that ftate, they are excluded on application of moifture. Such are _thofe of certain pennated polypi, difcovered by _ M. Trembley(r): Why may not the germs of the loweft clafs of animalcula be of this kind? The poflibility becomes probability, and this ad- vances a ftep fill farther, by our finding that the germs or ovula of fimilar races of infufion ani- malcula, poffefs the qualities nearly of vegetable feeds and the Trembleyan polypi. If the example of vegetable feeds refifting boil ing heat would induce us to believe that the germs of our animalcula might do the fame, the fuppofition is’ fingularly ftrengthened by other arguments, the moft immediate and direct, de- duced from the animals and eggs themfelves, Duhamel obferved, that a beetle, which feeds on grain, did not die at the heat of boiling water ; and Schaeffer found one fpecies of caterpillar that fupported: as much. The afflertion of fuch cez lebrated naturalifts deferves all credit. If from animals inhabiting climates {o temper- ate as ours, we pafs to the confideration of thofe that live in the warmeft regions, and confiding in the moft credible hiftories, they certainly multiply, and are moft numerous, notwithftand- ing the exceflive heat. Apamea and the Cape of (x) Bonnet, Corps Organilfes, a: 2. L. ANIMALCULA OF INFUSIONS. 4Yy of Good Hope abound with animals of every fize and figure, though the thermometer, in the fhade, rifes to 111°(1). Equally abundant is Carolina, where it alfo rifes in the fhade to'122°, and high- er. it has been demonftrated, that the direct ‘heat of the fun is twice that of the fhade, and fometimes thrice in the hotteft countries, there- fore this ‘heat in Apamea and the Cape of Good Hope fhould be at leaft 189°, and in Carolina will exceed 212°(2). If animals live at fuch heat as {1) Haller, Phyfiolog. T..2. it is not clear what country the author means by Apamea; feveral regions have that name.—-T. (2) Affuredly this is an error; for it is very much to be doubted, nay, I incline to deny altogether, that in any part of the globe the heat of the folar rays is nearly double that of the fhade. By the few experiments made in hot countries, the difference is not many degrees. In Scot- land, I have feen a thermometer, in an ordinary fitua- tion, expofed to the fun, rife to twice the heat of the fhade. But that was from refle@ion, and the heat that the furrounding fub{tances had acquired. It has afcend- ed to 118° or 120°, which was from the fame caule, as experiments demonttrated. The author is not the only perfon who fuppofes the di- rect heat of the fun is twice that of the fhade. Haller, an illuftrious phyfiologitt, and other naturalifts, think it may even be more. At Montpellier, he fays, it has been fo great as to roaft an egg, Phy/iologia, tom. LI. p: 32. which would be between 150° and 160° at leaft. As 46 ANIMALCULA OF INFUSIONS. i, as in Carolina, will furpafs that of boiling water, and their eggs fuffer no injury ; and if there are animals At Benares, when the thermometer in the fhade ftoad at 100°, it rofe only to 110° in the fun. When it ftood in the fun-fhine at 113° and 118°, expofed to a hot wefterly wind, it was 104° and 110° in the fhade, Philofophical Tranfattions, 1793-—In Caffraria, when the heat was 102° in the fhade, it was 106° in the fun, Barrow’s Travels in Africa —At Goree, in the fhade, it was 86°, in the fun 99°, Memusire, Fournal de Phyfique, 1788, p. 224. Annales de Chimie.— At Gondar, in Abyffinia, the thermometer rofe from 81° or 82°, in the fhade, to 113° in the fun; it is not impro- bable from fome difturbing caufe, Bruce’s Travels—But the moft furprifing accounts of folar heat are that in Paris 1793, while the thermometer in the fhade was 94°, it ftood at 144° in the fun, Annales de Chimié, tom. 18.—-At Mont- pellier, in the year 1705, in the fhade it was about 100° ; expofed to the rays of the fun twenty-eight minutes, it rofe to 212°, the heat of boiling water, Memoires de I’ A- cademie Royale, 1706, p. 12. 13.—I cannot avoid fufpec- ing that the conclufions from both thefe inftances have been erroneous; that the heat has, in the former cafe, been owing to fome furrounding objects, or the reflection of a neighbouring wall, and in'the latter cafe that the inftru- ment has been imperfet. ‘J hermometers it has been thought were then open at the top ; ‘but it was certainly otherwife in general. However in each of thefe cafes, the heat might be very great. There is much reafon to believe, that, except the obfervations made at fea, molt of all we have are erroneous. ~The heat of many climates would be,to us almoft intoler- able. The greateft cuftom can hardly reconcile the inhabi- “fants of northern regions to the burning heat of the fouth- erm: ” < : Ty ANIMALCULA OF INFUSIONS, A7 animals in our temperate climates that can alfo fuftain it, what difficulty is there m admitting, that ern. Inawarm country, the negroes could not fleep for ‘cold when the thermometer was at 68°. Park’s Travels.— The heat in Cayenne is from 70° to 93°, Prelong, Memoire. In the town of Batavia in Java, while the laft Chinefe em- baffy was there, between 88° and 92°, Macartney’s Embaffy, Vv. 1. p. 251.—During Peroufe’s voyaze, the thermometers, when higheit, ftood at 95°, Voyages——They were in the fhips; and it is to be remarked that cold is greater at feas The greateft heat in Japan, while Thunberg was there, was 98°, Zravels.—In one excurfion in the Cape of Good Hope, it was 100°, Sparman’s Voyages.-—At Aleppo, 101°, Rufel’s Natural Hiffory of Aleppo—-At Fort George, on the coaft of Coromandel, the thermometer ftood at 104°, Philofophical Tranfactions, 1780. It was equally high in Paris 1720 and 1793, Kirwan on the Temperature of different latitudes, p. 75. Annales de Chimie, Tom. 18, Tn Goree, the heat was from 104° to 106°, Prelong, Memoire. —In the interior of the Cape of Good Hope, 108°, Bar- row’s’ Travels.—At Pekin, 1773, from 108° to 110°. Kirwan, p. 935 from Men, de Scavan. Etrang.——At Pondicherry, 1769, the heat was from: 111° to 117°, Gentil Voyage dans les mers de L’ Inde, tom. \. p. 490. 495-505- Browne one day faw the thermometer at 116°, Travels in Egypt and Syria. Bruce faw it ftand at 114° in Sennaar, and 419° at,Chendi. M. Monneron told Prelong, that at Maufulipatam, he had feen the thermometer at 118°, in the fhade: and an officer affured him, that he had feen . it rife to 131° at Podor. During a voyage there, the ther- mometer, in the cabin of a veffel, ftood at 133°, Adanjon Hificire Naturelle du Senegal, pebi. And this is the great- ; eft - 48 ANIMALCULA OF INFUSIONS. i that the germs of animalcula of a fimilar con- ftitution may exift. In confirmation of all this, I Ley eft degree of heat in the fhade that I have yet met with well authenticated. Although the direct rays of the fun are not fo powerful as the author fuppofes, the heat which various fubftances, from their peculiar nature, receive from them, is great- er than can eafily be imagined: and there may actually be countries where the heat of certain fpots does equal that of boiling water. We read of the fand fo hot that the feet can hardly be borne upon it. In Senegal, it was 168°; and Adanfon fuppofes, that the thermometer might have rofe higher had the tube admitted; and eggs har- dened in it, Hiff. Natur. p. 13%- At Marfeilles, it is faid, Dr Raymond found the earth heated to 170°; Kirwan on different Temperatures, from Dhem. de la Societ. Med. de Paris, 1778. But it depends entirely on the fubftance what heat it will receive. The fand of Goree, which confilts of bro- ken fhells, was heated only to 113°, Prelong, Memoire ; and we have feen that the thermometer in the fhade rifes al- mot as high. Some perfons have imagined, I know, that if the heat was as great as the author admits, all the rivers would boil. This by no means follows, for one fubftance is not only ore eafily heated than another, but will receive more and retain it longer; and at Marfeilles where the earth was heated to 170°, the fea was only 45°. The like has been found in other inftances, and is daily evinced in water in m particular. From all thefe fa&s, we are warranted to conclude that » there may be places in the world, where in particular fituations, and aided by collateral circumftances, fome ani- ’ mal eggs or vegetable feeds may be expofed to heat not inferior I. ANIMALCULA OF INFUSIONS. ~ 49 { may relate an obfervation by M. Sonnerat, cor- refpondent of the Academy of Sciences, concern- ing the heat of certain waters in Lucon, one of the Philippine Iflands. They were fo hot he could not bear his hand in them, and the thermometer rofe to 187°. Yet, to his great aftonifhment, were fifhes {wimming there (1). I am conftrained, by philofophical fincerity, now to think otherwife of the germs of certain in- fufion animalcula than I did at the time of publifking my Differtation, when it did appear to me poffible their germs in general could refift the heat of boiling water. This was a deduétion from vegetable feeds and eggs perifhing at that heat: but the facts narrated here, which were then unknown to me, have induced me to alter ‘my opinion. Though the germs fo often referred to are not deftroyed, at leaft for fome time, by boiling heat, the animalcula thence produced perith at 108°, a degree remarkably inferior. This has been al- ready obferved, and not without furprife, but none ewill remain on bringing the example of plants eo) eta Be D and inferior to that of boiling water ; it may even furpafs it ; -but itis a very different confideration whether thefe eggs and feeds will not lofe their fertility ; eggs undoubtedly will when they are in that ftate, if they have the various parts commonly afcribed to an eco.—T. (1) Obfervations fur la Phylique, par M. Rozier, tom. 3. . , 50 ANIMALCULA OF INFUSIONS. E and animals into confideration, as they can fuf- tain fo much lefs heat than feeds or eggs. How- ever, the rule has an exception in the germs of the higheft animalcula ; for, whatever may be the caufe, they can fupport lefs heat than the animals themfelves. The animalcula die at 108°, but the germs are not developed after 95°. We are un- der the neceflity of admitting, therefore, that the nature of the germs of the higher and lowerclafles, is very different relative to their faculty of refitting heat ; which is fully coincident with all I have faid of vegetable feeds, and what fucceeds in eggs. Peaie, lentils, wheat and lintfeed, for the molt part, became fterile at 189°; trefoil vege- - tated at 2122; and M. Duhamel’s wheat at 234°: and although the difference has not been fo fenfible in the eggs of the animals mentioned above, it is fufficiently perceptible in thofe of another kind. The eggs depofited by certain butterflies on the under fide of leaves, as well as thofe that fome infects depofit to a northern af- pect, perifh at 79°. ‘Twenty degrees more will hatch the eggs of other infects; and that heat even feems neceflary for their exclufion. Such are thofe inferted by afili in the hard hide of oxen, cows, or bulls; of particular flies, that infinuate them into the nofe or frontal finus of fheep, goats, or deer; and of others, which depofit i. ANIMALCULA OF INFUSIONS, gt depofit them in the rectum of the horfe (1). The fame may be faid of feveral fpecies of worms breeding in the human body, and in calves, where the heat is about 99°. If there is fo much fimilarity in the powers of animalculas germs, and the eges of other ani- mals, in refifting heat, there is ftill more relation between animalcula and the animals themfelves ; for the fame heat is fatal to both, or they die at degrees not much different. Though thefe connections between germs and eggs, between infufion animalcula and other ani- mals, afford additional convi¢tion, that all the operations here are according to the known and ordinary laws of nature, without recurring to imaginary forces, {till we want further informa- tion to acquire more particular, more enlarged, and more correct notions of a clafs of beings, | which their wonderful minutenefs has removed to fuch a diftance from us. Yet our curiofity is fingularly excited concerning them, from the fa- mous fyftems of generation to which they have given rife, by their myfterious mode of reproduc- tion, and the uncommon qualities conneding them with the reft of animated nature. ‘ Here ‘ another univerfe begins,’ fays M. Bonner, * of which we the Columbus and Vefpucius have @ but diftinguifhed the fhores, and defcribe them D 2 © not (1) Vallimneri, 52 ANIMALCULA OF INFUSIONS. 1. ¢ not unlike the manner of the firft American * navigators.’(1). After Mr Needham, I have at- tempted to make little excurfions in this univerfe. I have endeavoured to penetrate the Continent, to view the inhabitants, and have not failed to ; give naturalifts a faithful account on my return. | But from new excurfions, and by exploring the country with greater diligence and leifure, I per- ceive my narrative is very fuperficial to what may be given. ‘This is what I have begun to communicate to the reader in the preceding chap- ters, and which fhall be profecuted in the fubfe- quent. What above all fhould be inveftigated is the nature of the inhabitants of this microfcopic world. The nature of an obje@ is difctovered from its properties, that is, its relation to other beings. The more analogies there are, the great- er {cope is there for comparifon; and the more comparifons we can make, our knowledge of it acquires greater extent. My principal purpofe in thefe new refearches fhould therefore be, to in- fitute the greateft poffible number of compari- fons between animalcula and other animals. I have already made fome experiments on them with heat, and I ihall now proceed to fpeak of others ; and firft of what is directly the reverfe of heat, namely, the influence of cold. | CHAP, (1) Corps Organifes, T. 2. ' ak: I. ‘ ANIMALCULA OF INFUSIONS. ga GHAP. IV. INFUSION ANIMALCULA AND THEIR GERMS EXPOSED TO VARIOUS DEGREES OF COLD. Animancuna were tranfported from the heat of the atmofphere to the cold of an ice-houfe. It muit have been a fevere change, in the heats of Auguft, to be removed from 84° to 36°. The only alteration I could perceive was fome relaxa- tion of motion ; but they did not feem to fuffer farther, though they remained there feveral days. The experiment was diverfified by expofing them to the cold of freezing, which I did by burying the veflels of infufions in ice. Confider- able part of the animalcula died on the fourth day : of twenty-two infufions, thofe of feven only were alive. Thefe feven were kept buried in ice, and vifited from time to time. In eleven days, the animalcula of two had perifhed, but thofe of the other five were flill living at the end of two months ; nay, one fpecies feemed more numer- ous. Befides the feven infufions already full of animalcula, two, which were yet fterile, from being lately made, had at the fame time beer put among the ice. In fome days, 1 know not D 3 how 54 ANIMALCULA OF INFUSIONS. i. how many, they produced a legion of moft mi- nute animalcula. In the courfe of the following winter, animal- cula were expofed to new trials, and the refult cor- refponded with that formerly obtained. Though under the freezing point, the infufions continued fluid, from the vegetable oil they contained, and not a particle of ice was to be feen: yet the ani- malcula of many died, except fome more robuft foecies, on which I determined, for that reafon, to make further experiments. During this winter, 1 put the animalcula that the cold had not been able to kill without the window in an exceflively cold day. The thermometer fell to 19°; and the infufions, hitherto preferving their fluidity, were covered with a thin cruft of ice. Breaking this cruft, and applying fome particles to the microfcope, in the parts not completely hardened, I faw animalcula ftill alive, immerfed in litle caverns of ice (1): but in the portions abfolutely frozen and dry, they were dead and motionlefs ; nor did they revive after melting the ice. Where the water was perfeCtly fluid, the animals were quite vivacious (2). This (1) The author means, he took the pieces when begin- ning to freeze; for water expofed at 19° would very foon become a folid lump of ice.——T. (2) The illuftrious Muller of Copenhagen has met with fome ie ANIMALCULA OF INFUSIONS. 55 This was not enough. 1 was eager to fee what happened as the water gradually froze.—A large drop of infufion being prepared, it was adjufted to the microfcope. ‘The circumference, that is, the thinneft part, froze firft. The animalcula retreated from the edge to the interior of the fluid. As the freezing advanced, they {till re- ceded, until collected in a mafs in the middle of the drop, where it was yet fluid. When this alfo froze, the life and motion of the animalcula ceafed. On repeating the experiment, they again fled to the centre, and died there as the drop hardened into ice. ‘Two other glaffes being filled with fi- milar infufions, they took an hour to freeze; and this infinite army of animalcula had fo concen- D4 trated fome fpecies that have furvived the congelation of infu- fiens ;—a fact which it has not been my fortune to witneis : and I muft fuppofe, he convinced himfelf the infufions -_-were perfectly frozen. Quaedam (i. ¢. Animalia Infuforia ) rigorem frigoris fuftinent aquaque gelu foluta, eodem nu- mero, vigoreque priftino circumnatant, alia gelu affecta periere. Thus does he exprefs himfelf, in his freatife on Infufion Animalcuia, Leipfic, 1773, 1774. Il regret that this work did not come to my knowledge until too late to ufe itin the text of my manufcript, which was al- ready tranfcribed. The lofs can only be repaired by notes; particularly as the author agd myfelf have fre- quently remarked the fame facts, or difcuffed analogous problems. 56 ANIMALCULA OF INFUSIONS, - I. trated in the middle, that very few were frozen ~ in the reft of the infufion. What I have hitherto related proves that thefe’ fpecies of animalcula do not perifh at 13° under freezing: but do they perifh becaufe cold has deftreyed them, or becaufe the infufions have loft their fluidity, for I have uniformly found, when infufions dried up, the animalcula were ir- recoverabiy dead? ‘The matter was dubious, nor could it be elucidated unlefs by farther expe- riment. It was neceflary to augment the cold below 19°, and at the fame time prevent the fluid from freezing. Both the one and-the other | were eafily accomplifhed, by means of artificiak cold, or a mixture of falt, fhow, and common water, in which animalcula that had died at 19° were put. It is well known to philofophers, that water’ does not lofe its fluidity at 20°, nay, at 21° below freezing, if at perfect reft, which is attained by inclufion in a veffel, and re- moval. from all external motion. Thus I dif- covered that. 19° had not been fatal to the ani- malcula but the freezing ef the infufions, fince at 12° all were alive and fwimming about, though with much lefs velocity than ufual. Some fpe- cies could fupport no more, for they died. at 12°, though the water was not frozen, but began to be covered with a thin film. Two {pecies ftill furvived, and perhaps, or even without perhaps, | might * Is ANIMALCULA OF INFUSIONS, Lyi might have fapported a greater degree, had F _ been able to keep the water longer fiuid (1). The germs of the animalcula were likewife ex- pofed to cold. New infufions being made, and the veflels hermetically fealed, I expofed them to moft intenfe cold produced by a mixture of finely: pounded falt and fnow ; the thermometer fell 2° below o. The infufions were frozen fo hard as: to require above half an hour to melt where: the temperature of the air they were removed: to furpafled the temperate degree (2). But the. germs had not fuffered the fmalleft injury, as all the infufions, though conftantly remaining in veflels hermetically fealed, produced every {pecies of animalcula at the proper time. Little is faid of cold in my Differtation, but it has been obferved, that the cold of fnow, or, which is the fame, that of freezing, killed infufion ani- malcula.' It is confirmed by the facts ftated here: and we fee in addition, that all animalcula do not yield to that degree, but fome can bear 14° and others more. Thefe things completely quadrate with (.) Dr Blagden cooled boiled diftilled water to 20° without freezing. He does not feem to conlider that keeping it at perfeét reft is the caufe of Huidiey. Philofo- poical Tranfactions, 1738.—T. (2) The temperate degree in Reaumur’s thermometer. I can neither procure one of them marked with the tem- perate degree; nor can i difcover from the Author’s own memoirs what it is. Probably it may be between ¢1° and 56° of Fahrenheit.—T, 58 ANIMALCULA OF INFUSIONS. Fi with the animals bearing the greateft analogy and the neareft to animalcula, I] mean infects. Some races do not die at 11° below o, while others perifh at 10°, or at moft at 7°. Many cannot fupport fimple freezing, and others ceafe to live at cold far inferior (1). There is this difference between infufion ani- malcula and infects expofed to cold; the former are fufficiently lively to preferve the action of their members ; the latter at freezing, and fome before it, lofe all vivacity, and affume the appearance of dead bodies. However, there are a few infects which, in this refpect, may be compared to ani- malcula; befides the podura of Linnaeus, which inhabits the fnows of Sweden (2), I have feen the eels of vinegar retain motion at an intenfe cold. Vinegar does not freeze fo foon as water; fome kinds did not freeze at 16°; others moré fpirituous at 7°; and the anguillae always moved while it remained fluid. Eels, like animalcula, ‘infenfibly become moticnlefs on encreafing the cold; they ftill move while a thin cruft covers the vinegar ; but the freezing being augmented, motion ceafes, and they are extended in a ftraight line, or in one a little curved. If fudden aid is brought, by melting the ice, they will certainly recover; but if the ice is allowed to harden more, hepaspupalls | (RO ee 4 melting will not bring them to life (3). iam) The (1) Reaumur, Memoires fur les Infeétes, tom. 2. 5. (2) Fauna Suecica. (3) Dr Power obferves, that the eels of vinegar may be frozen i PRS ees I. ANIMALCULA OF INFUSIONS. 59 The relation between infects and animalcula extends to the originating principles of both. In- tenfe cold neither deftroys the germs of animal- cula nor the eggs of infects. The year 1709 is celebrated for its rigour, and the fatal effects it had on plants and animals. The thermometer fell to 1°. Who can believe, exclaims Boer- haave, that the feverity of this winter did not deftroy the eggs of infects, efpecially thofe expof- ed to its influence, in the open fields, on the naked earth, or the branches of trees? Yet, when the fpring had temperated the air, thefe eggs produced as after the mildeft winters (1). frozen and thawed feveral times, and they will ftill be as lively as ever. Fifcher has feen a fpecies of taenia refift freezing eight days, and the hydatis cellulofa has fur- vived it as long ; Virey fur les Vers. Muller expofed a glafs veflel of water containing various minute animals to _the cold of freezing for twenty-four hours. ‘The ice was then melted, and the bodies of the animals appeared dead during twenty-four hours longer that they were examined. But on the following morning he faw the Cypris pilofa, a fmall fhelled infe&t, and the Cyclups quadricornis, which is one of the monoculi, as lively as ever bath males and females. Some fmall water beetles alfo recovered. Entomoftraca feu Infedia tefacea quae in aquis reperiuntur, p. 5, 6.—T. (1) Since that period, there have been winters more fevere. In France, during December 1788, the ther- ‘mometer fell confiderably lower, and in feveral other tem- ‘perate European climates. ‘There is a memoir on the fubject alfo containing fome judicious remarks on thermo- meters by M. Gauflen.—Memoires de la Societe Kes Sciences Phyfiques de Laufanne, tom. 3.-——T. ;* 60 ANIMALCULA OF INFUSIONS. k I have expofed eggs to ‘a more rigorous trial than the winter 1709. Thofe of feveral infects and among others of the filk-worm moth, and elm butterfly; were inclofed in a glafs veffel, and buried five hours in a mixture of ice ‘and fal gem; the thermometer fell 6° below o. In the middle of the following {pring, however, caterpil- lars came from all the eggs, and at the fame ais as from thofe that had fuffered no cotd. In the following year, I fubjected them to an experiment {till more hazardous. A mixture of ice and fal gem, with the fuming fpirit of nitre, reduced the thermometer 22° below o, that is 23° lower than in 1709. Aa were not in- jured, as I had evident proof by their being - hatched. Combining all thefe faéts, we conclude that cold is lefs noxious to germs and eggs than to ani- — malcula and infects. Germs in general can fupport 2° below o: whereas of animaleula, fome die at freezing, and fome about 20°. The eggs of many infects continue fertile at 22° below o, © while the infects die at 16° and 44°. This I have feen in filk-moths eggs, and thofe of the elm butterfly; and although there are caterpillars and chryfalids able to refift great cold, I have uniformly found it to be ina lefs degree than their eggs. What can be the caufe of fuch a difference? The queftion has already been agi- tated when fpeaking of heat; and in the fame manner i ANIMALCULA OF INFUSIONS. 61 ® manner as infufion animalcula and infects can refift cold lefs than their germs, fo do they lefs refift heat. A caufe for the difference has alfo been attempted to be afligned, and what has been faid will apply to the prefent cafe, which the reader may fee by refuming the paflage. ‘There is ftill a more obvious caufe: iniedts killed at 16° and 14° are fo penetrated and frozen by the cold, that their members do not yield to the preffure of the finger, and feem perfeét ice under the knife. This does not happen to eggs, though fubjeGted to a much greater ‘intenfity., Their humours remain fluid, even at the greateft ‘cold, as may be feen by crufhing them with the nail. Perhaps this is derived from conftituent {pirituous or oleaginous parts, or from fome principle adapted to abate the power of cold (1). If eggs do not freeze, it is probable the included em- bryos do not freeze. Is there any thing won- derful, therefore, that they then furvive cold which is fatal to them when produced? Pro- bably for the fame reafon, (and I fee no objec- tion. (1) To underftand this in’ its full extent would be er- roneous; for an egg will freeze by a great degree of cold: at the fame time, there feems to be a living principle which enables it to fupport cold without deftruction ; and when once that principle is deftroyed, cold more eafily operates. An egg was froze by the cold of o; after thaw- ing, it froze feven minutes and a half fooner. A new laid egg took half an hour to freeze in 15° and 17° ; but when thawed, it froze at 25° in half the time. Hunter on the Animal Occonomy.—T>» 624 ANIMALCULA OF INFUSIONS. 5 tion that can apply) animalcula concentrated in the germ, fupport a degree of cold they are in- capable of when developed. | Before terminating the chapter, fome reflec- tions fhould be made on the fmaller {pecies of animalcula which originate at freezing,—a phe- nomenon not remarked in my Differtation, when occafionally fpeaking of the feafon moft fit for their produétion, cither becaufe I had not ad- verted to the fact, or had never obferved it. We muft admit, that the germs of thefe moft minute animalcula expand when no eggs will produce ; for there is no inftance of any being hatched at the freezing point. But there is nothing fingular in it, if we confider what is the temperature we denominate freezing. The ancients believed it the greateft poflible degree of cold: modern experiment has demonftrated how much it may be augmented, either naturally or by art; and the faéts we juft now relate are an inconteftible proof. They fhew, that the cold of freezing is never feparate from a confiderable portion of heat. Can we defire any thing more convincing ? ff the ball of a thermometer is transferred from a mixture of fnow and falt to plain fnow, it will rife from 22° or 27° below zero to the freezing point again. Is not this a clear indication of the thermometer pafling froma cold to a warm fitua- tion, or, to fpeak more philofophically, from a place — I. ANIMALCULA OF INFUSIONS, 63 place where there is lefs heat to one where there ismore. Ifthetemperature of freezing retains a portion of abfolute heat, Why fhould it not de- velope the germs of the moft minute animalcula? It is needles to fay we are unacquainted with any fpecies of eggs that may be hatched by fo little heat ; had we never feen any but thofe of birds which require 104°, we fhould undoubtedly fup- pofe all others require the fame. A little initiation into the ftudy of minute animals teaches how many kinds produce at heat infinitely lefs: Such are the eggs of butterflies and many other infects, of frogs, toads, lizards, tortoifes, down to fome, as thofe of toads, which I have feen produce at 45°. If thefe eggs hatch at 59° lefs than thofe of birds require, what repugnance will there be to fuppofe that at 13 degrees lefs, or the cold of freezing, may hatch the eggs of other animals? Nor fhould it furprife me to be told of animals, whofe eggs would produce at much greater cold, after know- ing there are plants, beings fo fimilar to ani- mals, and many of them, which, amidft the ri- gours of winter, flourifh, are impregnated and frudtify, as winter aconitum, liverwort, (epatica nobile) narciffus, black hellebore, terreftrial mof-. fes, and corallines (1). Among (1) It is uncertain what the Author means by Coral- jines.—T, 64 ANIMALCULA OF INFUSIONS. I. Among the germs producing infufion animalcu- la, there is one fpecies that does not perith at boil- ing heat, whence the fmalleft animalcula originate, or, as we have termed them, of the loweft clafs. The refemblance in minutenefs of fuch animalcula, | and thofe originating at freezing, made me fuf- pect, that the germs refifting boiling might be the fame with thofe expanding at freezing. Rigo- rous experiment was neceflary to afcertain whe- ther it was actually fo. While feveral new infu- fions were buried in fnow, others hermetically fealed were expofed to boiling heat; and I examin- ed both at a proper time, but I never could dif- cover any fenfible difference in the figure, fize, organization, or motions of the refpective animal- cula; whence I think there is fufficient reafon to conclude they are identically the fame fpecies. ‘The identity of the animalcula eftablifhes the identity of the germs. ‘Two moft fingular pro- perties, therefore, exift in thefe minute animated beings ; ome the power of refifting the heat of boiling water; the other the peculiarity of ori- inating at freezing. fa I, ANIMALCULA OF INFUSIONS. 6 ww. CHAP. V. MORE ACCURATE AND EXTENSIVE CONSIDERATION OF THE EFFECT OF HEAT AND COLD ON ANIMALS. Hear and cold, we have feen, are two agents deftructive of animals, when extended to a cer- fain degree. We have alfo obferved, that all fpecies do not perifh at the fame intenfity; but fome can fupport more, and fome lefs, according to the hardinefs of their conftitutions. AI this, however, has been viewed only on a narrow fcale, and in a limited number of animals, and even thofe occupying the loweft rank im the icale of animation. Let us generalife our ideas, and confider the fats more at large. Let us run o- yer the different clafles and orders of animated beings, beginning with man, the moft noble, the moft fublime, and moft perfect of all.—— Such confiderations will afford an agreeable in- terlude, and leflen the ennui which attends the famenefs of a fubject. Though man, like other animals, being fub- ject to phyfical laws, mutt neceflarily be liable to perifh from excefs of heat or cold, he can fuftain -a degree of heat that might be fuppofed infup- Vor. J, portable. 66 ANIMALCULA OF INFUSIONS. I, portable. Coinciding with Boerhaave’s fenti- ments, it is commonly believed, we cannot exit in an atmofphere warmer than blood-heat. So that illuftrious philofopher concluded, becaufe he faw certain birds and quadrupeds die. at 149°, which is 50° more than human blood (1), This opinion is ill founded ; fince there are coun- tries inhabited where the atmofpherical heat is greater than that of our bodies. ‘Thus, in Apa- mea and the Cape of Good Hope, it is 113° in the fhade (2); to which the natives muft be ex- pofed. In Carolina, it jurpaffes that of the human body; for the thermometer falls when taken from the air in the fhade and put in a perfon’s mouth (3). In warm baths, we are fometimes fubjeCted to more heat than in the hotteft cli- mates. Certain waters are 113°, and others fo much as 120° (4). | There is the fame fimilarity in the facts related ef cold to thofe related of heat. Boerhaave thought the utmoft degree of cold that could happen was zero in Fahrenheit’s thermometer, or 142° below freezing by Reaumur’s; at which, he remarks, men, animals, and vege- tables foon perifh. Experience proves that, in different parts of the globe, cold is greater. Ac- cording to what the Parifian academicians relate, in (1) Chemia. Tom. 1. (2) Cap. 4. (3) Haller, Phyfiolog. T. 2. (4) Faller, ibid. i, ANIMALCULA OF INFUSIONS. By in fome winters at Peterfburgh, the thermometer fell 29°, and once 33° below o (1). The cold at Quebec exceeded it, for the thermiometer fell to 42° (2). That at Torneao, obferved by Maupertuis, was {till greater, as it fell to 51° (3). But this which appears extreme, compared with what we witnefs, cannot bear comparifon with that fometimes-felt in many parts of Siberia, as Tomfk, Kirenga, Jenifeik, where the thermome- ter lias been feen at 90°, 128°, and even 178° below o (4). Such dreadful cold, we cannot deny, was per- nicious, nay fatal. In Peterfburgh, at—29°, the face could not be kept uncovered above half a minute (5): and at Torneao, where the ther- mometer fell—51°, thofe expofed to the air felt the breaft as if lacerated. Nor is it uncom- mon for the inhabitants ef thefe.cold.climates to lofe fome member, as a leg or an arm, durine winter (6). Similar and more terrible are the effects in Siberia: yet, in other parts of the earth, cold is perhaps more intenfe. Such may Captain Middleton have experienced in Hudfon’s Bay, as he has communicated to the London Royal Et 2 Society. (1) Chem. ibid. (2) Hiftoire de L’Academie Royale de Sciences, 1749 {3) Voyage au Cercle Polaire. {4} Hilt. de PAcad. Roy. (5) Ibid. {6) Maupertuis, ibid. 68 ANIMALCULA OF INFUSIONS. i: Society. —All the liquors, not excepting brandy, froze within their houfes, and the beds in their apartments were covered with a coating of ice three inches thick,—though the walls of the dwellings, where they had buried themfelves, were ftone, and two feet thick,—the windows very fmall, and clofed with {trong boards moft part of the day,—and they had great fires continually burning. The Dutch fuffered equal cold in Nova Zembla; where the rigour of the weather was fuch, that, in a clofe hut, and with a con- ftant fire, it was with great difficulty they could keep their feet from freezing. Their cloaths were always covered with ice; and their wine, though very ftrong, was dealt out in lumps of ice (I). The (1) Here the author’s dedudtions are from erroneous experiments made by others; becaufe cold fo very intenfe has never been witnefled by modern philofophers. It is not impoffible, indeed, that there are countries where it is really as great, but they are yet unexplored. It was long believed, that no natural degree of cold ex- ifted which would congeal mercury. It was artificially frozen, and the thermometer fell feveral hundred degrees below the freezing point. Therefore, when travellers in the northern regions faw it {tand at—1o00° or 200°, they concluded that to be the real degree of cold: but the smercury in the thermometer was already frozen, and ra- pidly contracting into lefs bulk. The freezing point of mer- cary, it is now afcertained, i$ under—-40°: but if the cold exceeds ‘I. ANIMALCULA OF INFUSIONS. 69 The effects of cold to that degree too clear- ly demonftrate, that it would be fatal to the hu- man race, if unprotected againft it. I do not mean, ie 3 _ it exceeds this very little, it will defcend the fcale fome hun- dred degrees. In an experiment, where the cold was only a few degrees more than 40, the thermometer immedi- ately fell to—450° and 490°.—Cavendifh’s Obfervations on Mr Hutchin’s Experiments, Philof. Tranfac. 1783, p» 23> 25 The greateft cold that Acerbi obferved in his travels in the north, was—13°. Mackenzie experienced 16° ; but his thermometer was then broken.—Travels over the N. Con- tinent of America. ‘The greatef{t cold at Montreal in North America was—16°. 18°.—Philofophical Tranfactions. That experienced by Captain Cartwright, on the coaft of Labra- dor,—25°.— Journal of a Refidence on the Coaft of Labrador. On the fame coaft, by M. de la Trobe,—30°.—Philo/: Tranf. 1782, p. 198. ‘The cold at Peterfburgh and Mof- cow has been from—30° to 39°.—éa Petropolitana, Nov. et Vet. var. loc. Mercury has froze at Prince of Wales Fort, Hudfon’s Bay, and Albany Fort.—Philof Tran/. 1793, p- 368. 1770. M. Patrin fuffered—35° in Siberia ; and quickfilver froze.—Fournal de Phy/fique, 1791, p. 88. But even thefe degrees have been far furpaffed at Ouftioug Velikoi, in the government of Vologhda, lat. 60°. 50. N. where the thermometer fell 83° below Zero, in De- cember 1787; and, in January the fame year, fo low as 103°. The fenfations excited by fuch exceflive cold are incon- ceivable to us, who live in temperate climates. “I can- * not exprefs the pain of refpiration at 35°,” exclaims M. Patrin : “ boiling oil feems to fill the lungs. Even in the “ clofeft 70 ANIMALCULA OF INFUSIONS. I it will be fo abfolutely, but only. relative to the condition of the perfons expofed. With regard to what was fuffered by Middleton and the Dutch in Nova Zembla; fhut up in huts, they led a quiet and fedentary life, which undoubtedly pro- motes the action of cold; I do not think myfelf miftaken in affirming, that, well cloathed, and taking plenty of exercife in an open country, they might have braved as intenfe cold without danger. In the winter nights of our temperate climate, it is fometimes much more than freez- ing, and ‘one cxpofed to it without any motion would really die; but preferving fufficient mo- tion, we might fuffera greater degree. Thus. the Paris academicians, though accuftomed to a climate « clofeft carriages, one is fuffocated by this piercing cold.” Its other effeéts are no lefs terrible: rocks and trees are fplit with reports like cannon. There is a perfe& calm, and fo thick a mift prevails, that nothing can be dif- tinguifhed a few paces diftant. Magpies, crows, and fparrows fall dead to the earth; nor are quadrupeds and. the human race fecure from danger. ' The pernicious eonfequence of cold is vifible in all ani- mated nature. Plants are neither fo abundant nor lux- uriant as in the warmer regions. Animals are fewer; they are lefs diverfified; and, in general, their fize is fmaller, Something is wanting to expand the organic fyftem ; nay, to create that beauty: and variety which are signi inthe genial temperature of the South, and which it is fo pleafing to behold.—T. Ij ANIMALCULA OF INFUSIONS. 71 climate as temperate as ours, began their aftro- nomical obfervations amidft the woods or moun- tains near Torneao, before the {now lay deep up- on them, and the intenfe cold had not encreaf- ‘ed to---51°, as it afterwards did ; however, it was fuch, that all liquors excepting brandy froze, _ and a veffel could not be taken from the mouth without drawing blood, for the froft had glued it to the lips. The favages of the moft northern climates con- tinue to. hunt during the coldeft weather ; and io true is it, that motion alone preferves life, when any misfortue threatens deftruction, they acceler- ate death by reft(1). There can be no bettez proof of the efficacy of motion againft cold than the narrative of the Dutch who wintered at Spitz- _ bergen, a country fituated in 78° of north lati- tude, and by common confent allowed to be the coldeft in the world. Thofe who had fhut them- felves up in a hut, in the beginning of the feafon, died one after another. The cold was fo excef- five that no fire could warm them ; whereas thofe who had gone into the open air, and employed themfelves in the chace, in carrying wood, or any other corporal exercife, preferved health and vigour (2). Beg . From (1) Boerhaave, Praelectiones, Haller, Phyf tom. 2. (2) The fame has invariably been proved by the ac- counts of thofe unfortunate perfons condemned to win- ter “I ta From what has been faid may be judged the va- riety of heat and cold that man can fuffer, begin- ning with heat equalling or furpafling blood heat, and defcending to the horrors of cold fo far ex- eeeding freezing, which fhews that man is not ne- ceffitated by nature to inhabit. certain determinate parts. of the globe, but to live, multiply, and exer- cife his fovereignty over all, without finding an ob-- ftacle in climate. It is otherwife with quadrupeds. ‘They are difperfed over. the earth ; fo that fome are limited to warm climates, fome to temperate, and fome to cold ; nor has any fpecies yet been found adapted to live im all indifferently. The lion, elephant, tiger, leopard, and panther, inha- bit only the warmeft regions ; when tranfported- to the temperate, they become ineapable of pro- pagating, and foon perifh in the cold. Although the domeftic animals, fo ufeful to us, are not in- . jured by warmer climates, they cannot. live in colder. Such are the horfe, ox, and fheep. The elk, rein-deer, and ermine, inhabitants of the north, are never found in fouthern countries ; and fo far from being able to exift there, they do not live in temperate climates. At leaft this has. been ter in fuch inhofpitable regions. Air and exercife always preferved health, while ina@ivity uniformly fubjected them to difeafe. However the death of a great many feems) to have enfued from. improper food.—T.- ANIMALCULA OF INFUSIONS. - 1 as kL ANIMALCULA OF INFUSIONS. 7% been found with the rein-deer ; its naturalization. has often been attempted in France and Germany, but inftead of multiplying they always perifhed(1 5. The law reftraining quadrupeds to their native’ countries is liable to modifications ; for there are fome that can exift and multiply in temperate though originally from warm climates. The rabbit and guinea-pig are inftances of the former ; the beaver and lynx of the latter(2). Birds may in this inveftigation be confidered as divided into two clafles: Of thofe inhabiting cold, temperate or warm countries, fome do not wander far from their native place, or do not change their climate. Others have no fixed abode, but change according to the different fea- fons, being necefflitated to it either by the fcanti- nefs (1) Buffon Hiftoire Naturelle, tom. 14. (z) It is very true, that the animals which have been removed all at once from cold to warm climates, and the reverfe, have ceafed to propagate their {fpecies. However, there are feveral exceptions, and more will be known in proportion as natural hiftory continues to be further cul- tivated. Perhaps the ceffation of multiplying their fpecies arifes from the great and fudden change: but if one ge- neration was removed two degrees farther north or fouth, propagation would moft probably continue. If their pro- geny were removed two degrees more, and fo proceeding by fhort diftances, every generation, there is great reafon io fuppofe, would continue fertile, and the animal be natu- ralized in any climate.—T. 78 ANIMALCULA OF INFUSIONS. Bid: nefs of food, or from inability to bear the winter, or even a flight degree of cold. We have faid that Boerhaave thought 149° immediately killed certain birds and quadrupeds. Surely 50° above blood, heat is very great, and cannot but be intolerable to many races of ani- mals; yet we muft acknowledge it may be borne, and that it is fo by many {pecies inhabiting the torrid zone, and other very hot regions. And it appears to me, that we fhould reafon on heat which birds and the reft of animals can fupport as we reafon on the cold. As thofe in the northern climates can fuftain exceflive cold, fo can thofe in the fouthern fuftain exceffive heat. It is eafy to afcertain the greateft cold that either - cetaceous or fquamous: fifhes fuffer: it will al- ways equal that of the water which they are in, confequently in frefh water lefs than freezing, elfe it would not continue fluid. Thofe inhabit- ing falt waters, as the fea, will fuffer a little more. ‘Thus fithes are fecured againft the rigour of cold to which innumerable animals are fo much expofed. No lefs are they theltered from the burning heat of the atmofphere, excepting thofe living in fhallow waters, and on that account more or lefs fubjeCted to the influence of the air from the predominating feafons or the climate. From fome obfervations, we know there are carp living in warm {prings that experience blood heat — as i, -ANIMALCULA OF INFUSIONS.» 95 heat (i). I took feveral river carp for experi- ment. When the water they were in had been heated to 106°, they exhibited no fign of uneafi- nefs. At 109°, they began to ftruggle, and died at 116°. Experiments were made on_ other fifhes, as eels, tench, lampreys, but none could bear fo much heat. Whence, by analogy, thofe inhabiting warm fprings fhould fupport greater heat : and of this the fifhes we have juft mention- ed afford ample evidence (2). But of all known animals, reptiles and infects {tand in greateft dread of cold, and feek heat the moft. ‘The heat of the fun may be called their foul. Then they are full of fenfation and motion; and as that luminary is more powerful, fo do their activity, vivacity, and boldnefs increafe. ‘The venomous kinds, as fnakes and f{corpions, are more formidable, and their poifon more danger- ous. But cold produces an oppofite effect. In- numerable infects perifh on the approach of win- ter, and moft of both them and reptiles that fur- vive would encounter the fame hazard, if not protected again{t it. In temperate climates, all feek a fafe retreat when winter comes. Some, as {corpions, and many {pecies of flies, retire to the rents of walls, or under the tiles of houfes; others are concealed in the midft of ftones, the clifts {1) Haller, Phyfiol. Tom. 2. (2) Ibid. Tom. 4. 76 ANIMALCULA OF INFUSIONS: Ii clifts of trees, or holes in their trunks, as vipers, fnakes, cantharides. Some are fecured in the caverns of mountains, in fubterraneous abodes and the cellars we make, as fpiders, flies, mufkitoes, naked fnails, and beetles. Others find a genial warmth in dunghills during the rigour of win- ter. The bottom of waters, and the bowels of the earth above all, give fhelter and retreat to moft reptiles and infects. Yet, in the whole of thefe afylums, though fufficiently defended from the fatal effeéts of cold, they fuffer from its influ- ence in the moft fenfible manner. Their limbs become torpid, and they remain im a lethargic flumber the whole winter. But among quadrupeds, birds, nay, perhaps, among fifhes, there are fome that experience a kind of lethargic torpidity not unlike that of reptiles and infe&ts. To fay nothing of frogs, toads, lizards, and the like, among quadrupeds which dwell in water or in the earth all the win- ter, hedgehogs, land tortoifes, feveral rats, the marmot and dormoufe, are alfo overcome by le- thargy. Some in fociety, and fome in folitude, conceal themfelves in the trunks of trees, or are hid in the earth. Cold has the fame influence on bats ; they are found ftiff and motionlefs in hollow trees, or the rents of walls, or hanging to the vaults of fubterraneous caverns. Some {, ANIMALCULA OF INFUSIONS, 77 Some birds are alfo fubject to torpidity. At the end of fummer, hundreds collect, clufter to- gether, and plunge into water, where they re- main the whole winter in heaps, and fhrunk within themfelves. The learned reader already anticipates that I fpeak of fwallows. The fac is too well circumftantiated, too well authenticated, for any one to be hardy enough to call it in quef- tion. Many refpectable and credible perfons de- clare, they have not only beheld flocks of fwallows collect and plunge into pools on the approach of winter, but oftener than once ‘have feen clufters of them taken out of water, and even from be- neath ice. The doubt therefore is, whether the fwallows of which thefe refpeCtable authorities fpeak are ours, that is, thofe conftruting an earthen nett in our houfes, and refiding with us dur- ing fummer, or whether they are {trange fwallows, by which I mean a bird fimilar in colour, figure, and fize, but of a different nature and {pecies. For many years I have endeavoured to folve this gueftion. Experiment has taught me, that ani- mals which are torpid in winter become lethargic alfo in other feafons, if fubjected to the requifite degree of cold; fo that, on expofing a frog, a dormoufe ( /orcio mofcardino) or a lizard, to the cold of freezing, in fummer, while moft vivacious, it foon becomes torpid, and is in a flate of torpor till the cold ceafes. Suppofing the fwallows of our 78 ANIMALCULA OF INFUSIONS. aL our country were thofe drawn torpid out of water, and from beneath ice, I imagined they might be- come torpid and motionlefs if fubjected to the fame degree of cold, and thought of expofing | fome to the temperature of an ice-houfe, gradu- ally bringing them from warmer atmofpheres, as of a cave or an apartment adjoining to the ice- houfe ; for, during the month of Auguft, to carry them all at once to fuch cold might be too fud- den achange. But all the fwallows in the ad- joining chamber died in three hours, without my being able to difcover whether they had firft fallen into a lethargy. The cold was not great, as the thermometer ftood at 43°. Other fwal- lows had the fame fate. Whence I may conclude, that the fwallows found in water or under ice ° are of a fpecies fpecifically different from ours, becaufe they perifh at a fmall degree of cold (1). This (1) Since the author wrote this, he made the following experiments on fwallows, which may tend in fome mea- fure to elucidate the natural hiftory of thefe birds, which has hitherto been fo obfcure. ‘ Auguft 23. 1792, the thermometer being at 76°, four houfe fwallows, (hirundo domeftica) confined in a glafs veffel, were buried in fnow. In an hour, they had not fuffered in the leaft, and flew about the apartment. They were returned to the veffel, and the cold increafed. In 124 B ANIMALCULA OF INFUSIONS. 79 This experiment, which is mentioned in my An- notations ‘ 124 minutes, the thermometer ftood at 9°; they were very feeble, but kept their eyes open ; they moved when touch- ed, and endeavoured to efcape. The thermometer fell no more. In 60 minutes, fome figns of animation were in- dicated by two, but the others appeared dead. However, this was only afphixy, for the heat of the atmofphere re- animated them, and in 68 minutes they had recovered their natural vivacity. ‘Of two fwallows expofed to 1°, one died in ten, the ether in fifteen minutes. * Two window fwallows (hirundo urbica) expofed to 2° and 3° of cold, died in 21 and 40 minutes. ‘ Six martins (hirundo apus) were expofed to 8° for three hours. The firft hour they were reftlefs ; the fecond their motions lefs frequent ; the third they feemed motionlefs though without lethargy. Their eyes were open, and they moved on being touched. Expofed to the atmof- phere at 74°, they recovered. ‘ In another experiment with the fame martins, the thermometer fell to 3°; one died in fix minutes, two more in twenty-five; the other three appeared dead, but reviv- ed on expofure to the atmofphere an hour: however, they died irrecoverably when returned to the veilel ten minutes longer. ¢ Some naturalifts think, that the bank fwallow (hirundo riparia) conceals itfelf in holes during winter ; and the er- ror afcribing the fame to window. fwallows, arifes from confounding Bo ANIMALCULA OF INFUSIONS. Lb notations on La Contemplation de la Nature, a work confounding the one with the other. Montbeillard con- ceives, that inftinét may induce them to conceal them- felves in the earth during winter. ‘ Achard, coming down the Rhine in 1763, procured fome birds, evidently fwallows, quite torpid and inanimate, drawn from their fandy holes. Being put next his fkin, they recovered, and flew away. But this obfervation only proves, that there exift fwallows fubje& to real lethargy without determining what fpecies. Therefore, notwith- ftanding all that has been written on it, the queftion is ftill dubious. In two years, I opened above fifty fwallows holes on the Banks of the Po, without finding any thing but their neft or its remains, which demonftrates that the owners had gone to winter in other climates. This re- calls an obfervation by Collinfon, who did the fame, and he difcovered nothing. ‘Onthe 15 of June four fwallows confined in a glafs veflel were immerfed in a mixture of foda and ice. The thermometer fell to freezing ‘without affecting them; I confined them again, and the thermometer fell to 10°. In twenty minutes they were taken out. They could fcarce- ly move, or ftretch their wings; their eyes were fhut, ne- verthelefs they gradually recovered, and in half an hour flew about the apartment. ‘ The experiment was repeated ; they lived thirty minutes at the fame cegree. Put on their backs on a table, they were motionlefs at firft; then after many efforts they re- covered t. ANIMALCULA OF INFUSIONS. Sy work tranflated by me(x1), I find confirmed by | M. De Buffon, in his firft volume on birds, pub- lifhed. covered their natural pofition, and walked about the cham- ber, but had not ftrength to fly. As the animal functions returned, refpiration gradually became more fenfible and quicker ; the eyes opened, motion and life were re-acquir- ed. In three hours the fwallows could fly. ‘ They were again expofed to the cold of o twenty mi- nutes. Two expired ; the other two revived in five hours, but were unable to ufe their wings. Is this torpor a real lethargy fimilar to what is moft improperly called the ileep of many animals? Immobility of the body, almoft extinguifhed refpiration, fufpenfion of the fenfes, and re- covery of them are ftrong prefumptions. But the fame fymptoms may attend real afphixy, fimilar to that of ani- mals immerfed a certain time in water, or brought within the {phere of fome mephitic gas: an afphixy effentially dif- ferent from lethargic fleep, which may be continued {feve- ral months without injuring the exiftence of the animal, while the other will foon deprive it of life. ‘ To afcertain this point, I entered with greater eager= nefs on new experiments, as they afforded me an oppor- tunity of correcting an error, when formerly {peaking inci- dentally of the lethargy of fwallows. In one of my notes to La Contemplation de la Nature, 1 faid, feveral fwallows which were kept in an apartment adjoining to an ice-houfe, where (1) Firft printed 1769, 1770. The experiments’ were made five years béfore. Mor. 1. Ly 82 ANIMALCULA OF INFUSIONS. Is lifhed 1770; where he obferves, that, with the fame defign, he confined feveral fwallows in an ice-houfe,. where the thermometer ftood at 43°, died without be: _ coming lethargic ; whence I concluded, that thefe birds were incapable of fupporting cold. In my Opu/coli di Fifica’ Animale e Vegetabile, 1 repeated the fame remark: the fa& was true, but I deduced a falfe confequence; for they bear a much: greater degree without inconvenience. « Several {pecies were fhut upin wicker bafkets, covered with wax-cloth to preferve the humidity, and buried in how. In twelve hours, they were ftill vivacious, and crept clofe together to fecure themfelves as much as poffible againft the cold. The next twelve hours, they were in the fame ftate. Two could fly languidly about the ice-houfe. In thirty- five hours four were dead, two houfe fwallows, a bank fwal- low, and a martin ; the reft were fo weak, that they could neither ftand- nor fly, neither did they make any effort to efcape. Still, thefe fymptoms rather indicated infirmity than lethargy: their eyes were not fhut, and they refem- bled dying birds in every thing. Not one was alive in te hours more. All perifhed in 48 hours in another experi- ment. . “It was neceflary to cover the bafkets with wax-cloth; for two fwallows, expofed without this precaution, died in two hours and a half, and were as wet as if they had been drenched in water ; which has certainly been the cafe witlr thofe mentioned in my note on La Contemplation, as I re- collect perfectly well that they were very humid. * Nine 1; ANIMALCULA OF INFUSIONS, $3 ice-houfe, but without ever feeing them become _torpid ; and they uniformly perifhed on remain- ing expofed any confiderable time. He thence concludes it impoflible that this bird becomes F 2 lethargic ! Nine more were confined in an ice-houfe: they lan- guifhed without becoming lethargic, infenfibly loft their ftrength, and died in 41 hours. ‘Thefe animals did not perifh from hunger, for others lived without food three days, three and a half, and five days, while the moft vi- gorous in the ice-houfe lived only 48 hours. Thus, the acceleration of death can only be afcribed to privation of heat.’—A. Thefe experiments very much elucidate the nature of fwallows in one refpect, but they aré not quite fatisfactory. The author féems to think that intenfe cold does not ac- ‘tually produce lethargy. If this is the cafe, it muft be admitted, that all the fwallows named here leave Britain in autumn and return in fpring; and that we have no proof as yet, that any birds taken torpid from the earth, caverns; rocks, or walls, were really fwallows. It is not evident, whether the author retains his opimion in the text, that fwallows have been drawn torpid from ‘ water. This has been fupported by learned men. It is admitted in a late tra@ by Fabricius on the winter {lzep of animals. ‘ All the experiments on fwallows are related in the au- thor’s hiftory of thefe birds. Neither that, nor his hiftory af Owls and Eels, in the fame volume, are yet tranflated into Englith, fo far as I know.—T: $4 _ ANIMALCULA OF INFUSIONS. 1 lethargic in winter; fo much the more, as he tearns from M. Adanfon, that common fwallows conftantly appear in Senegal during autumn, and difappear in fpring : and he conceives the Euro- pean fwallows, and thofe fubjet to lethargy, of different {pecies, though they have hitherto been efteemed the fame. : Neither are fome wanting in the immenfe tribe of fifhes on which cold produces a fimilar effect. Tench, if we may credit Pechlin, as quoted by Hal- ler, are of this defcription(1). In the beginning of winter, he has obferved them bury themfelves in the mud, juft as we have feen many reptiles and infects do in the earth. Speaking in gene- ral terms, fifhes are a clafs of animals enjoying the privilege of preferving action and vivacity, however cold the atmofphere may be, not only becaufe fluid water can never acquire a great portion of cold, but becaufe they may retire ftill deeper and deeper whatever is the cold it ac- quires (2). \ Whence (1) Ad Praelection, Boerhaav. T. 4. Haller, Phyfiok B§s (2) The poffibility of fifhes becoming torpid has been doubted. A: few experiments which I have made on fe- veral fmall fifhes feemed to indicate torpor. When ex- pofed to confiderable cold, though lefs than freezing, they funk motionlefs to the bottom of a veffel, and immediate- ly ee a i. ANIMALCULA OF INFUSIONS. 85 Whence does it happen that almoft all reptiles and all infeéts, at a certain degree of cold, lofe their whole vigour; their motion ceafes, and they affume the appearance of death ; while man, and the moft part of quadrupeds and birds, at an infinitely greater degree, retain their ori- ginal ftrength and vivacity? What can be the proximate, the immediate caufe of this apparent death in the former animals, and that it is not fo in the latter? No one that I know of, before M. de Buffon, fet himfelf ferioufly to confider this fingular phenomenon. According to him, the animals that become torpid are cold blooded. Such had he found the greater dormoule (1), the common dormoufe, land hedgehogs, and bats, which of themfelves have no internal heat, and only that of the atmofphere. Their blood refrigerates in proportion as the atmofphere refrigerates, which cannot take place with warm blooded animals from their internal principle of heat. ‘Torpidity muft enfue from this refrigera- tion, becaufe the ufe of the fenfes and limbs is 3 loft ; ly revived on removal to a milder atmofphere. Some, however, preferved a languid motion while the water was about 32°. Ia Cepede appears to confider fithes, in gene- ral, fubject to a degree of torpor; and he fays, the deeper the lethargy, the lefs of their fubftance is loft.—Hifvoire aes Poifons, T. 1. Difcours, p. 132. 133.-—T. (1) By him called Lerots. $6 ANIMALCULA OF INFUSIONS. Loins loft, and becaufe the blood probably circulates in the larger veffels only. Such does this aluthor “ob fuppofe the immediate caufe of torpidity in thefe | four animals; and he extends it to marmots, and all others fubje€t to torpor, as he is convinced . their blood is cold (1). I could have wifhed that fo plaufible an hypo- _ thefis had been true; but I have never found it accord with facts. In the firft place, it is not — the cafe that every animal becoming torpid has cold blood. Hedgehogs, marmots, and bats | certainly are not fo. Haller, who has diffeéted feveral hedgehogs, fays pofitively, he has always found their blood warm. Lifter, Robinfon, and Lancifi affirm the fame (2). I moft fully aflent to the opinion of thefe illuftrious phyfiologifts. The blood of three hedgehogs diflected by me was warm; fo have I found that of bats. M. de Buffon’s method was ufed to afcertain it. He imtroduced the ball of a {mall thermometer into the body of dormice by the mouth. He never faw the fluid rife: On the contrary, it funk fometimes one and fometimes two degrees; an evident fign that the blood was cold. But when- ever [introduced the thermometer into the mouth of hedge-hogs and bats, the fluid rofe to 99°, and even 102°, if kept eight or ten minutes, which demonttrates 7 (1) Hiftoire Naturelle, Tom. 16. 17. (2) Phyf. Tom. z. IF, ANIMALCULA OF INFUSIONS. 87 t demonftrates the heat of both to be the fame as _ our own (1.) As it was not then in my power to have mar- mots at. pleafure, I defired a much refpected friend, who could eafily obtain them,to undertake fimilar experiments (2). He did fo; and the re- fult proved, that marmots are not cold blooded, as M. De Buffon had fuppofed, but are endowed with an internal principle of heat, equalling that of other animals. He was pofitively affured of it, by keeping the thermometer in the axilla of _two marmots. The heat of one raifed' it to 90? in eight minutes, 20° above the temperature of F 4 the (1) Hunter found the heat of a dormoufe 80° and 85°, when the heat of the atmofphere was 50° or 60° ; when the animal was lively, 91° or 93°.. A thermometer intro- duced within the body and applied to the pelvis rofe to 99°, the atmofphere at 66°. The moufe being put an hour in an atmofphere of 13°, it rofe to 83°. In hedge-hogs, he obferves, Mr Jenner found the heat 48°, when they were torpid or the atmofphere 44°, and the heat only 30° in anatmofphere of 26°. But expofed to this cold two days, the heat in the rectum was 93°. So far from being torpid a hedge-hog was lively, and the bed on which it lay felt warm. Whence he concludes that ex- ceflive cold roufes the vital powers.—Ob/ervations on the Ani- mal Economy —V. (2) Sig. Giannambrogio of Milanan able chemift, al- ready well known in the republic of letters, by a moft e- laborate 88 ANIMALCULA OF INFUSIONS, ti, rhe atmofphere at the time; and in fifteen mi. nutes, that of the other raifed it to 93° (1). Some -laborate and learned differtation on Fox-tail, (Covetta) and ammunition bread. (1) It will be obferved, that, in the courfe of this work, much is faid of cold and warm blooded animals, and fome important conclufions thence deduced. Notwithftanding all that has been written on animal heat, the caufe is un- doubtedly very ob{cure. Experiments and reafoning have neither fufficiently coincided, nor been fo generally adopt- ed, as to entitle us to form pofitive opinions on the fub- jea, more efpecially when philofophers do not agree whether the living body has the property of producing heat or cold. Amphibia, reptiles, fifhes, infects and worms, are gee nerally believed to have cold blood. However, there are experiments on all but the faft that feem to indicate a principle of internal heat independent of the atmofphere ; fo that the thermometer will afcend when removed from the open air into their bodies. Yet many naturalifts de- ny that they have any principle of heat; and think the temperature of their bodies muft always be exadly the fame as that of the furrounding medium. But, in my opinion, fufficient accuracy in experiment has been ne- glected, and due attention has not been paid to the ftate of the medium where the animals previoufly were. A few experiments which I have made on the fubje&, even with thofe precautions, have been difcordant ; one thing how- ever s a ANIMALCULA OF INFUSIONS, 8g _ Some time afterwards I fucceeded in pt scuring two marmots.—The experiments made en them completely correfponded with thofe of my learned friend. In the open air, the thermometer ftood at 66°; when introduced within the throat, it rofe to 102°; therefore the fact, with refpect to all thefe animals, cannot be more decifive (1). How, in contradiction to the facts before us, which admit of no reply, can Buffon’s affertion fubfift, which is in exprefs terms—that he has found the blood of hedgehogs and bats cold ? - Without fuppofing his animals of a different fpecies from mine, end much lefs not to allow his ever is certain, namely, that all infe&s are not cold ; and although the heat of one fingly is not fenfible, the heat of a number colleéted is very confiderable. I kept a ther- mometer ina bee hive; it fometimes ftood between go? and 98°. The height did not feem entirely regulated by the temperature of the atmofphere, for it has been 80° and go? inthe hive, while 55° and 5.° in the fhade. When 62° in the fhade, it has been aslow as 82° in thehive. A number of bees collefted do not become torpid during winter. When the atmofphere was at 25°, which is cold weather in Scotland, I reverfed a hive, and introduced a thermometer among the bees, it immediately afcended to 710, and would perhaps have rofe higher.—T. (1) I believe that the author afterwards made a feries of inveftigations concerning marmots, but I have not been able to procure the work.--T, 90 ANIMALCULA OF INFUSIONS. I. his experiments credit, there is an eafy method of conciliating the differences: It is, That the French naturalift has made his experiments in winter, when the animals are deprived of fenfe and motion, and aétually are not different from cold-blooded animals, becaufe inclemency of the feafon has exhaufted every principle of heat. Experiment had taught me, as reafon itfelf would do, that neither bats nor hedgelfogs become lethargic unlefs their internal heat is diminifhed. From the whole it is evident, that, notwith-— ftanding M. De Buffon’s idea is ill founded, it is indubitable that refrigeration of the blood takes place in all animals experiencing lethargic fleep. Shall we hence conclude the lethargy an imme- diate confequence of this refrigeration? Let us confider the incipient torpor of an animal.—The influence of cold begins: it ats not only on the exterior, but alfo internally. Application of the thermometer will not allow me to doubt it ; and evinces, that the action of the cold is equally communicated to the fanguinous fluid and the fohds. Yet I am left in doubt, whether torpi- dity proceeds from refrigeration of the blood, of the folids, or of both. I try to analize the fact; and reflect whether there is any animal, among thofe becoming torpid, which, after pri- vation of its whole blood, will, for a confidera- ble time, preferve its original vivacity and vigour. Such 1. ANIMALCULA OF INFUSIONS, or. Such a one may perhaps afcertain the truth. If, after being deprived of the blood, this animal does not become torpid on expofure to cold, then the fole caufe of torpidity lies in the refri-- geration of the blood: if torpor does enfue, we cannot recur to the refrigeration of the blood, but to that of the folids, or to the influence that cold has on them. An animal of this kind is not only poflible, but it exifts,—there are feveral, as, frogs, toads, tree frogs, and water newts. In my experiments I have obierved, that all the blood being difcharged from the opened heart or divided aorta, thefe animals ftill leap for many hours, run, dive in water, and {wim to the top, retain a lively fenfe of fight and feeling; in a word, continue the exercife of every corporal funtion that they had before (1). I now repeated the experiments, and began with frogs.—-Several very vivacious were buried in {now ; part were untouched, and part of the number deprived of the blood, by endeavouring to evacuate it com- pletely from the heart and large veflels. In eight or ten minutes, fome were examined : the blood- ed and thofe entire were exactly in the fame {tate, that is, half dead, and not attempting to efcape, though at liberty. In fifteen minutes, I | drew (1) 'Thefe experiments are fpoken of in my work, De Fenomeni della Circolazione. 92 ANIMALCULA OF INFUSIONS. — [y' drew others from the fnow, fome entire, and others deprived of blood; they appeared motion- lefs, and as if frozen. All were replaced in the fnow, and in a few hours removed to a warm fituation. I attentively confidered what happen- ed. By degrees, the contracted ones ftretched, their eyes opened, they fhook themfelves, began to leap and efcape. Being again configned to the fnow, and taken out after a certain interval, © all exhibited the fame phenomena. There was not the fmalleft difference at whatever feafon the experiments were made. I found a remarkable correfpondence between tree frogs, toads, and water newts: the whole became lethargic in the fame manner, by the cold of fnow,—and returned to their former animation when removed from it, The coincidence of thefe facts obliges me to fay, that the failure of fenfe and motion does not arife from refrigeration of the blood, for it can- not take place where there is none, nor from the relaxed circulation of this fluid, but depends entirely on the folids, which, being powerfully attacked by cold, are in a condition very different from the natural ftate. What the new condi- tion is, may be difcovered from the phenomena of lethargic animals. ‘They appear contra¢ted, the muifcles have no longer their natural foftnefs and pliancy, but become hard and withered. Thus a ee vgs ANIMALCULA OF INFUSIONS. 9% Thus there is abfolute proof that the mufcular fibre acquires great rigidity, and it is fuch as muft materially prejudice its irritability: This is evident from the moft active {timulants not occafioning the flighteft contraction or corrugation. Irritability is commonly believed the origin and principle of life :. when it is fo much injured in the animals of which we fpeak, it muft occafion that lethar- . gy, that fimilitude to death which is manifefted. If this is the real and immediate caufe of tor- por in thefe animals, I cannot fee any reafon why it fhould not extend to all others fubject to torpi- dity. It is impoflible, indeed, to deprive the warm blooded animals, lable to torpor, of what Buffon fuppofes the efficient means, for their nature does not admit of them living without blood. But their muf{cular rigidity, alfo, is certain ; and it renders them infenfible to every ftimulus while in the le- thargic flumber. I have feen it in bats. I fprinkled them with falt, bathed them with warm water, pricked them with needles, and laid open the-pec- toral mufcle, methods moft powerful to excite ir- ritability, but all were ineffectual, while they were opprefled by profound lethargy. The electric fpark, fo fit above all {timulants to awaken irrita- bility, was equally ineffectual. If the irritability of warm blooded animals is fufpended by means of cold the fame as that of the cold blooded, and if the ceflation of this power, as far as ap- pears H4 ANIMALCULA OF INFUSIONS. iF pears to me, is the only and immediate caufe of lethargic fleep in the latter, I do not fee why it + may not alfo be extended to the former. The fame degree of cold does not occafion tor- pidity in all the animals fubjedt to it. Very lit- tle is neceflary for fome ; others require confidera- bly more ; and others an exceffive degree (1). What we defign temperate, which is fo mild to our fenfations, occafions torpidity in dormice ; a little more affeéts bees; fnakes, vipers, and many fpecies of bats: What affects frogs, toads, newts, and others, approaches freezing, but this is far from operating on marmots, as they re- quire 11 degrees below freezing (2): The dif ference (1) Réaumur Memoires fur les Infectes. (2) At different feafons, however, the fame cold feems to produce different effets. On the 18 of July, when the heat is generally between 60° and 70°, I cooled the water with fix Hydrachnae down to 38°. They all funk to the bottom, and remained completely torpid. In ge- neral, they yielded to 42° or 40°, except one, called, by Muller, a variety of the Papillator (but apparently con- Rituting a particular f{pecies in Scotland), which refifted 38° a long time, and then funk down along with the reft. All revived at a moderate heat. On the 5 of December, I took five hydrachnae from water at about 44°, and put them into water at 36°. - - . 4 7 ee ee They became more languid. The thermometer gradual- ly ee ee hi ANIMALCULA OF INFUSIONS, ys ference of cold required to occafion torpor, muft arife from the different nature of the muf- eular fibre, which in fome animals is more fuf- ceptible of it than in others. If the power of cold is encreafed, torpor degenerates into death. The reafon afligned by phyfiologifts for the death of man and animals from cold, is certainly very plaufible. The contraction of the cutane- ous veflels forces a reflux of the blood to the in- ternal parts of the body ; whence is occafioned the infenfibility and ftiffmefs of our fingers and the extreme palenefs of the body. Cold be- coming more intenfe, the internal and large vei- fels contract, and the reflux of blood is greater ; but thofe of the brain, being better defended by the cranium from the injuries of the air, are not fo liable to contract. Blood flows copioufly in the ly fell to 32°; and a crutt of ice, a quarter of an inch thick, formed on the top. Still the animals could move, though languidly, and a very faint motion was percep- tible in the legs of one. Thus the water remained fome hours. In twenty hours after the experiment began, the thermometer ftood at 36°. None of the hydrachnae were torpid. Experiments were at the fame time made on feveral other aquatic animals. Squillae and gyrini did not be- come torpid at 32°. Perhaps this fubject deferves furthet confideration.—T. 96 ANIMALCULA OF INFUSIONS. ft. the arteries, covered and protected from the at- mofphere, while the jugular veins being contra¢t- ed, it is with difficulty returned to the heart. A fenfible relaxation in the circulation will enfue, which, encreafing as the intenfenefs of the cold advances, will end in reft, and the animal will die. In the northern countries, it is not unufual that a coup de froid kills men on the fpot. ‘The caufe has been fuppofed nearly the fame. The lungs, expofed to the immediate action of the cold air, are fuddenly contracted, and impede the paflage of the blood from the right to the left ventricle of the heart. Thus, according to thofe authors, death proceeds from obftru€ted circulation (1). J am fully convinced this may be the real rea- fon why numberlefs animals die, that is, all thofe neceflitated to perifh when the circulation is ftop- ped; but there are many that live, at leaft fome time, when the circulation of the fluids is fuf- pended, or even when they are entirely taken away. The death of animals by cold mutt there- fore (1) According to the moft authentic accounts, when men are expofed to intenfe cold, an irrefiftible defire to ‘fleep enfues, which ends in death. Thus, it is not impro- bable that men may be in a degree of torpor and revive. —T. i. -ANIMALCULA OF INFUSIONS. 9 . fore be afcribed to fome other caufe than obftrua- ed circulation (1). To difcover the immediate caufe of death, I made obfervations on animals killed by cold fimi- lar to thofe I had made on animals becoming le- thargic at a {mall degree. The phenomena at- tending death are thefe. Rigidity of the mufcles gradually encreafes until, the whole body hardens and freezes. Freezing firft appears at the ex- tremities, whence it extends to the centre. If taken to thaw in milder air, the parts acquire their former pliancy, but the animal will not re- vive. Its death is in confequence of having been frozen, but we cannot fay it is from freezing of the blood : firft, from the reafons above given ; fecondly, becaufe feveral animals being expofed to cold, fome deprived of blood, and others un- touched, all died in the fame time. Thus, death of this kind proceeds from the folids being frozen. At a certain degree of cold, the mufcles grow ri- gid, and the irritable power is deftroyed ;_ thence proceeds their apparent death. Cold more intenfe freezes the mufcles; freezing deftroys the power Vou. I. G of (1) In my work De fenomeni della Circolazione, I have demonftrated, that many animals live a confiderable time after privation of the whole blood, alfo wken circulation is fufpended, by tying up the aorta. Ihave fince obferv- ed this in yeptiles, as vipers, ferpents, eels, &c. 98 ANIMALCULA OF INFUSIONS. Le . of irritability, and real death is the confequence. The mufcular fibre is contracted by cold; the liquid, rendering it moift and pliant, is infpiffat- ed; but freezing vitiates the ufe of this fluid, by, changing it into fo many icicles, whofe fharp and cutting points lacerate the fineft and moft delicate parts of the fibre. The mufcular flefh is then difcovered to be full of thefe icicles; and, when one attempts to twilt or bend it, fracture enfues, as of.a friable fubftance. CHAP. VI. INFUSION ANIMALCULA EXPOSED TO VARIOUS ODOURS AND LIQUORS; TO ELECTRICITY AND A VACUUM. Cirrtain odours are to infedts the moft viru- lent poifon. Such has Reaumur found the oil of turpentine, and the fumes of tobacco. The odour of camphor, according to Menghini, has the fame effect ; and its vapours are full. more efficacious when burnt(1). In my inveftigation, I propofed-to inftitute the greateft poffible num- ber of comparifons between known animals and thofe fo remarkable as the animalcula of infu- fions, the better to penetrate their origin, nature, | and (t) Commentar. Acad. Bonon. T. 3. \ _ ‘k ANIMALCULA OF INFUSIONS. 99 and properties, which induced me to refolve not toneglect trying the effe& of odours upon them. I began with that of camphor: the refult was precifely the fame as has been obferved in infects. The vapours of this refin occafioned fudden agi- tation and difcompofure in the animalcula: they endeavoured to retreat from the malignant fumes, by retiring deep into the infufions. If the va- pour was rare, they were long of dying; but when denfe, it immediately became fatal. The odour of the oil of turpentine killed them, but not fo foon as camphor. The fumes of tobacco were not fatal for fome hours: but thofe of ful- phur, inftantaneoufly (1). The liquids ufed in my experiments were chiefly oleaginous, becaufe thefe are mortal to infeéts : they were no lefs fo to animalcula. 1 omit the fpirituous or corrofive, which killed them in a moment; as alfo falt water, vinegar, ink, brandy, and fpirit of wine. We could hardly believe that human urine produces animalcuia, after ftanding a few days, as Hartfoeker has obierved, if the fame phenome- non was not daily obferved in vinegar, which is full of microfcopic eels, though a fluid equally deftructive to animalcula as urine. Repeating G2 the (1) Odours penetrate deep into water, but to a very different degree : Some will traverfe feveral inches, others not one. There are a few curious experiments on the fiub- ect. Senebier Phyftologie Vegetale. Tom. 5. chap. 6.—T. 100 ANIMALCULA OF INFUSIONS. ee the experiment, I found it perfectly true. A dark cineritious pellicle covers the furface of urine that has been fome time at reft ; and here are the animalcula generated. They are of a roundifh figure, and in fize like animated points(1). The fame race of animalcula always - continues in urine, kept feveral months; but no new fpecies ever appears. One might fulped, that they are produced after the urine has loft its acrid and corrofive principle : but, befides re- taining the charatteriftics of real urine, it is fall fatal to other animalcula ; nor do thofe of ftale urine die when put into that which is recent. ‘Therefore this fpecies muft be effentially different from common infufion animalcula. It is well known, that the electric fhock kills ani- mals ;. and as they are {maller, fo are they more eafily killed. A battery ten feet {quare with dif_- culty kills a cat ora dog (2); but very few feet is enough for a pigeon; lefs for a goldfinch or canary; and thus diminifhing as the animals are {maller. It appeared that a fhock of moderate ftrength would deftroy animalcula ; but not being poffeff- ed of an eleCtrical machine, I availed myfelf of the affiftance of Sig. Pietro Mofcati, then my colleague in the royal univerfity of Pavia, who, --in (1) Leeuwenhoeck thinks he faw animalcula in the re- ~ cent urine of a mare, De ortu et defluvio capillorum.—T. (2) Prieitley. Hiftory of Eleétricity. . i ’ 1. ANIMALCULA OF INFUSIONS. 10r in addition to {kill in electrical experiments, had a machine of confiderable power. He was’ fo obliging as frequently to comply with my philo- {ophical requeft, and fubjeét infufions full of ani- malcula to the eleétric fhock. They were invul- nerable, and as lively after receiving the fhock as before ; nor was there any difference, though two, three, or more {parks were drawn from the infufions: ‘The weaknefs of the fhock cannot be objected, as two or three killed a ae newt, or fimilar {mal} animal. I was accuftomed to communicate the refult of my experiments to M. Bonnet before publifh- ing them, becaufe this ilfuftrious naturalift feem- ed to wifh to. partake of my little difcoveries. Among the reft, I mentioned that which Dr Mof- cati had made. He anfwered, that he had fhown .M. de Sauffure my letters, who had repeated our electrical experiments, but with oppofite effects, which he afcribes to the great humidity of the air ef Lombardy preventing electricity from being fo powerful as at Geneva. He adds, that M. de Sauflure would himfelf inform me of his refults, which he did very foon ; and I tranicribe them here, fuch as M: Bonnet fent to me, in the fol- lowing letter (1) : G 3 | < My (1) M. Bonnet afterwards publifhed a collection of his letters to his learned correfpondents. I have collated all that are quoted here with thofe in that colleion, and corrected any errors or inaccuracies. — I. 104 ANIMALCULA OF INFUSIONS: Ct : © My Solitude, 15 February 1772. ‘It was but lately, my celebrated friend, that - ‘M. de Sauffure tranfinitted me his experiments: ‘on our animalcula. Certain of the pleafure you will derive, I do not delay a moment in fending them. You will judge of my opinion by your own; and I have no-doubt will be as ‘well fatisfied. his is a fubje&t equally new ¢ and curious for the meditation of philofophers 5. nor. is it to be queftioned, that in future we shall: be able to diverfify and extend this new kind “of phyfico-electricity. Buta plan mutt firft be pointed out; and there is no fmall merit in opening up the unknown fources of truth, which experiment is to accomplifh. I can: not retard the pleafure you will have in M. de Sauffure’s letter. n wn tay w“ wn “A “ Geneva, 8 February 1772 ‘{ return, Sir, with a.thoufand thanks, the *¢ letters you had the goodnefs to fend. I have “* perufed both with extreme fatisfaction, but re- “ gret that you tran{mitted my letter on the “< tranfparency of germs to Sig. Spallanzani, for “it is not worthy of that honour, and ftill lefs of ‘¢ your eulogium on it(1). Behold where you ‘have conveyed that trifling epiftle; being in *¢ your’s, it will alfo be publifhed by Signior Spal-. i ** Janzani) («) Vide M. Bonnet’s fecond letter at the end of this. — Trad. k ANIMALCULA OF INFUSIONS: 83 * Janzani, though I never thought it would have *“ been printed, which it little deferves. “¢ At another time, I have told you, Sir, but it cannot be repeated too often, my extreme plea- “ fure in perufing the beautiful feries of Signior Spallanzani’s experiments and obfervations. “¢ He is fit for your friend and fellow labourer. ‘ With him are found that order, that analyfis, ‘ that judt and rigorous logic, of which your owt * writings afford an example. “You know that alfo have been occupied with infufion animalcula ; and you yourfelf n- Lal an ec ** have honoured me by inferting fome of my re- fults in the republication of your Palingenefie. It has pleafed me to obferve, that my experi- €¢ é Lay n mh ‘ments entirely coincide with Signior Spallan- é - Lay zani’s obfervations. ‘7 had attempted; as he did, to repeat ¢¢ Mr Needham’s fingular experiment, which ~“ confifts in imtroducing the halves of corn “< pickles into flices of clay, that they might ger- «¢ minate at the furface of water: I alfo faw ani- ““ malcula originate as in common infufions ; but *¢ neither difcovered thofe zoophytes, nor vege- *‘ table roots producing animalcula, which Mz ‘* Needham had feen rather with the eyes of an ‘¢ imagination heated by the love of theory, thati -“ with the calm fenfes of a philofopher. G 4 ae 104... ANIMALCULA OF INFUSIONS. 1 “‘ Thad feen the minute round heads which “¢ terminate the filaments of mould burft when “* moiftened, and difcharge a globular duft. I had “¢ communicated it to Baron Haller, who {peaks €¢ of it in the article Mucor, in the new edition. “* of his hiftory of Swifs Plants; but I had nei- “ ther witnefled nor fufpected the furprifing in- “¢ deftrudtibility of this duft, which Signior Spal- ‘¢ Janzani jultly fuppofes the feed of the plant. ‘I had long endeavoured to kill infufion ani- «* malcula by electricity, and without better fuc- * cefs than Sig. Mofcati and Spallanzani; but: “* more exaQt obfervations have at laft given op- “ pofite refults. You may communicate them “* to the latter if you think proper. «© Some drops of rice infufion, full of animal- “‘cula, were put on a glafs flider four inches. “long and one broad, with the rounded point “of a quill, and the drops drawn out fo as to: ‘¢ form an uninterrupted line from one extremity “¢ of the glafs to the other. When the flider was. “* applied to the machine, fo that the eledtric. <¢ fluid paffed continually, and without fhocks “and fparks, they moved about, and did every. “< thing as ufual. In general, I have obferved,, “that fimple electricity, that is without fhocks <‘and fparks, never produced the leaft effect ; “but, when the flider was fo difpofed that a, “ftrong - fe ANIMALCULA OF INFUSIONS. 10g - ftrong fpark fuddenly paffed from one end to “ the other, the whole were killed almoft inftan- “taneoufly, and any that furvived died very “foon. The Leyden phial was not required ; a “ fpark from the conductor, without any more “¢ apparatus, was fufficient. ‘¢ T was curious to learn what happened at the “¢ moment of the fhock, and difpofed my flider ** fo as to obferve the animalcula. After a vio- “lent fhock, they were always in agitation. “¢ Some were immediately reduced to granuli, a “mode of death to which you know thefe ani- “mals are very fubje&: Polypi, which in the «manner of multiplication refemble them fo *¢ much, often perifh in the fame way. The ani- “¢ malcula remaining entire, revolved a few fe- “‘ conds in the liquid, then {topped at the bot- *« tom, and died on the fpot, without any change “© of figure. ** The fpark is fatal, though they are in a “ greater quantity of water. I filled a elafs tube “* two lines in diameter and four inches long with “* water full of animalcula. Five or fix very “ ftrong fparks drawn through it killed them all. *¢ But the confequence was different, on taking ““tubes four or five lines in diameter. The “ electric fluid, difperfed in fo great a {pace, is * not of that denfity to lacerate the body of ani- ** malcula. © One 166 ANIMALCULA OF INFUSIONS, i “One fact has to me appeared moft fingu- ‘lar. You know, Sir, that the fparks, which -* we with to dire& through a fubftance, often *¢ slide over the furface rather than penetrate it, «© even where the fubftance is very permeable by “¢ electricity. Matters may be fo arranged, that *¢ fuch a phenomenon will infallibly fucceed; and | have frequently prepared a bafon of water {fo “© as the fparks would pafs over a furface a foot ‘long without penetrating the water. This i ‘¢ found to have the fame effect on animalcula as “ when the fparks pafled_ through the water it- «¢ felf, While my eye was applied to the microf- “cope, the moment fuperficial fparks were «¢ drawn, I faw the whole animalcula in agita: “tion; fome reduced to grains, and the reft im: “ mediately die. ** Do not imagine the poflibility of my being “ deceived, by fuppofing the fpark glided over ‘¢ the furface, when it in reality penetrated the “¢ water, for the difference is too fenfible. ‘Vhat ‘¢ which glides appears moft brilliant over the “whole furface; that which penetrates pafles “¢ without being feen. Perhaps you will fay one ‘¢ portion of the eleétric fluid pafles within while «the remainder paffes without. Doubtlefs this “may be; was it fo, it feems that fuch a divi- “ fion fhould weaken the {park ; whereas it ap- * pears more brilliant and fonorous than ufual. “ Thefe ee }. —s ANIMALCULA OF INFUSIONS. ' 1OF “ Thefe fuperficial fparks do not go deep? “ they have no effect on animalcula {wimming ** five or fix lines from the furface: only few are ** killed, which certainly are near the top when “¢ the fpark pafles: the reft remain vivacious and “* well. At this depth, a very ftrong fhock, fuck “as is capable of melting an inch and a half of “iron wire one twelfth of an inch in diameter, * has not the leaft influence on them. “ Thefe, Sir, are the refults of my moft intereft- “¢ ing experiments on electricity operating on ani- “ malcula. I with they may fatisfy you and Sig: _“ Spallanzani, if communicated to him, or that “¢ you will tell me what more I ought to do. Two “¢ circumftances fhould be mentioned; one that “the experiments were made on the infufion “animaleula of wheat, hempfeed, and maize, and the refuit has always been uniform; the ** other, that the animalcula were of the largeit “ fize that infufions produce.” M. de Sauffure’s experiments befides being in- genioufly conceived, and happily executed, ap- pear decifive ; and they induced me to fuppofe, fome unforefeen accident had oppofed Sig. Mofca- ti’s ; and perhaps that the exceflive humidity of the air of Pavia, as the Genevefe profeflor had thought might be the caufe, particularly as our experiments. were made in winter ; I wifhed to repeat them ina more favourable feafon, but that 108 ANIMALCULA OF INFUSIONS. — fy that became impoffible, as Sig. Mofcati was foon afterwards re-eftablifhed in Milan, his native place. However, in two years, having procured an ex- cellent machine, I repeated them myfelf, and the confequehce could not correfpond more with M. de Sauffure’s refults. The animalcula were firft expofed to the difs charge of the Franklinian battery: Upon it was put a little {pot of pitch, with a very fmall hole through the centre, full of infufion ; the fpark was drawn through this hole. Not one animal. cula of thoufands in the hquid furvived the fhock a moment ; many were wounded and reduced by the electric vapour, and many appeared untouch- ed. The fhock was diminifhed by :charging the battery lefs, but the effect was the fame. ‘The quantity of liquid expofed to the fhock was en- creafed, by drawing a right line on the fpot, two thirds of an inch long, and two lines broad, pro~ ‘ceeding from the central hole. ‘Then the fhock was tran{mitted through the whole fluid. It was a real thunderbolt to the animalcula ; all immedi- ately died. If the breadth of the line was en- creafed but not the length, a change enfued. So long as only two lines broad, none efcaped, but when more than that, the animalcula either were not injured or did not die for fome time. ‘Thofe within the limits of two lines were ftunned, and continually revolved on themfelves ; the vertigin- ous 1. ANIMALCULA OF INFUSIONS, 109 ous motion diminifhed by degrees, and in a quar- ter of an hour entirely ceafed. ‘Thofe not fo near as two lines furvived longer; the activity and livelinefs of the moft diftant evinced they were not effected by the electric fluid. If, inftead of en- creafing the breadth of the liquid more than two lines, it was produced from the centre of the fpot, fo as to reach the circumference, which made full five inches in length, the fhock e- qually killed the animalcula throughout the whole. Such were my experiments with Frank, lin’s battery. | Let us now fpeak of a fimple fpark drawn from the conduGor. Here I ufed the fame ‘pot of pitch which was put on the conductor. The {park drawn through the central hole feemed more brilliant and fonorous. The central hole a- lone was filled with fluid, or a little channel was added of various dimenfions on the fpot. Every time the fpark was drawn through the hole, all the animalcula perifhed, but three or four were required to kili them in the little channel. Many fubftances. are better conductors of the ele€tric fluid than water ; and where the fhock was weak, I was unable to direct it through the channel, efpecially if very long and narrow. But the fluid did penetrate and aét upon it, as ap- peared from the crackling when the conducting rod was applied ; and this trifling electricity was {ufficient KIO ANIMALCULA OF INFUSIONS. L fufficient to kill animalcula, which I could not have believed. To learn whether the eletricity diffipated by metal points, fixed to conduGors, would deftroy animalcula, I applied a drop of infufion to one, and found it to be fo only if the eledtric fluid paffed for fome time from the point. It was evident, in fhort, that every fhock, however feeble, was always fatal. But fimple electricity, that is which operates filently, had no effect, as M. de Sauflure alfo obferved. As to the kind of animalcula, I can freely affirm that experiment has been omitted on none of the vaft variety, and electricity has been alike fatal to all. a The perfect coincidence of my experiments with M. de Sauffure’s leads me to publifh them ; but the friendfhip I had always borne to Sig. Mofcati, impofed the duty of firft inquiring whe- ther he had repeated our experiments as he pro- mifed, when I communicated them to the Ge- nevefe naturalift. I tranfcribe his anfwer, as he feemed to wifh it fhould be publifhed. It both proves that he kept his promife, and obtained new refults, which cannot but do great credit to truth. ’ ‘In your laft letter, you inquire whether I “have repeated the experiments which we made ‘fome years ago on electrifying animalcula, ~ * which i, ANIMALCULA OF INFUSIONS, {ii b| ‘ € Lal n ta) nN a = a ¢ 6 € € € Lay n 4 wn Lal nm a) which were then neither injured nor killed; More than once they have been repeated, with different and even oppofite refults, which I have alfo difcovered did not arife from the weakneis of my machine, fince fulminating ele¢tricity is not neceflary to kill them, but to the ‘method employed. When we made the experiments, we ufed a little brafs cup; and, towards its cen- tre, endeavoured to dire€: the fhock of the jar where the cup was fixed. We never killed one animalcule by this method; nor was I more fucceisful on repeating the experiment alone, at the moti favourable periods for electricity. But as you informed me that M. de Sauffure, whofe merit and accuracy in experiment I know and highly efteem, had feen them die; and as it had alfo appeared, that the fpark, inftead of com- ing from the liquid with the animalcula, efcap- ed from the circumference and fides of the vef- fel, I began to fufpect that, inftead of paffing through the fluid and ftriking the animalcula, it came directly from the metallic cup to the conductor, gliding over the furface of the in- fufion. I therefore changed the plan. Ona polifhed cryftal plate, well wiped, I put a little hollow piece of wax, and faftened two brafs wires, with obtufe points, from two oppofite extremities near the furface; one communicat- ed within, and the other without, the jar. This * apparatug £12 ANIMALCULA OF INFUSIONS. Ps a apparatus was placed before a compound microf- cope, made by Cuff, which his Excellency the Conte di Firmian had prefented to me. The hollow was filled with liquid, containing lively and vigorous animalcula; and I kept my eye intent on them, while another perfon work- ed the machine: I fucceeded thus in killing them with a fhock of no great ftrength, and with a fmall jar. The animalcula fuffered ei- ther by receiving the fhock or being in the vi- cinity when it pafled; thofe at the bottom of the hollow remaining alive. One thing I re- colleé&t to have particularly remarked, that the animalcula killed affumed a briftly appearance, like a microfcopic fponge, and were more opaque than the reft; from the fuperficial af- perities occafioned by the fhock, they feemed larger than when alive. I was in this manner convinced of the truth of the experiment; and being afterwards engaged in other matters, as I ftill am, thought no more of it. Excufe the ‘ brevity of the recital and the drynefs of the fub- ‘je; it does not arife from indifference to fuch agreeable fludies, but the neceffity which you, well know I am under of applying to fubjeés lefs interefting. I have the honour to be, with ‘the utmoft efteem and friendfhip, your moft de- voted, obliged fervant and friend, Milan, 6 “fan. 1774. Pietro Moscati.’ I a) a nv a n “ cal a” An tay Cay a an “ n ~ n “a a. e n an a a n P ANIMALCULA OF INFUSIONS. rey T have {till to fpeak of animalcula included in a ‘vacuum, which is the laft fubjeét that I propofed to difcufs in this chapter. —The confequences were different according to the difference of {pecies ; a vacuum was very foon fatal to fome, and others lived in it very long. Let us enter on detail. Several {mall glafs tubes, clofe at one end, were filled with various infufions. The tubes were very fall, and the glafs extremely thin, fo that applying the magnifier 1 might fee what pafled within when appended to the infide of a receiver. Some open tubes, full of the fame infufions, were kept in referve for the neceflary comparifons. Sixteen days privation of air did not injure the animalcula; on the twentieth day, they began to die; and on the twenty-fourth, all were dead. Thofe in the open air {till furvived, otherwife one might fay the natural term of Iife was expired (1). The experiments were repeated on more infu- fions of a different kind. Of fome the animal. cula lived a month in vacuo, and even thirty-five days: thofe of others died in fourteen, eleven, and eight days: and fome lived only two. The infufions mentioned in my Differtation were {j- Vout. H milar Theolog mm I's | 114 ANIMALCULA OF INFUSIONS. I. milar to thefe; their animalcula died in about two days (1). The nature of certain animals is wonderful. They continue their ordinary corporal funétions in vacuo a confiderable time. Vipers and faakes will creep, and leeches fwim in fluids. Some infects feed, and others perform, the work of ge neration (2): Such is the nature of animalcula. In a vacuum, they preferve their wonted mo- tions, afcending or finking, darting to the furface of the infufion, and diving into its deeps, or driv- ing before them the floating particles on which they feed. I fhall afterwards {peak of their fingu- jar modes of propagation ; and this alfo fueceeds - for feveral days in vacuo. In procefs of time, and according to the f{trength of the animalcula, motion relaxes and ends in death. It fometimes happens, but rarely, that, being taken from the receiver, and left expofed to the open air, they revive. | Thefe experiments have confirmed two obfer- vations in my Differtation; the ufual fterility of infufions in vacuo; and their fertility when the air was only rarified. No animal or vegetable fubitance macerated in vacuo ever produced a fingle animalcule: the reverfe uniformly happen- ed, on leaving a portion of air in the receiver. As much as keeps thirteen inches of mercury in equilibrio (1) Capitolo, 10. (2) Sperienze del Cimento. ‘ —_— I. ANIMALCULA OF INFUSIONS. 115 equilibrio is moft advantageous for them to origi- nate. ( Similar phenomena have occurred with the eges of animals. I have repeatedly put thofe of terreftrial and aquatic infects in the receiver of _an air-pump, but none were ever hatched, though they had all the requifites neceflary except air. From thefe and other analogous fatts is de- duced the neceffity of air for the developement of every animated being. While the animal is con- centrated in the egg, it enjoys the beneficial in- fluence of air by an infinity of minute pores throughout the egg, which have not efcaped the notice of naturalifts: when liberated from it, or the involucrum by which it was concealed in the womb of the mother, it receives the benefit of the air by other more evident ways. An im- menfe number of animals refpire by the moth, and many by apertures in the fides of the body, by the extremity of the abdomen, or by other parts. The breath enters the mouth of nume- rous channels at the furface, which condué the air by ramifications into the interior of the body. The animalcula of infufions, notwithftanding their apparent fimplicity of {tru€ture, exhibit an organ which we are f{trongly induced to conceive 4s intended for refpiration. And in this cafe, they more than ever ftand in need of the aerial fluid, which is evident by depriving them of it. There He are 116 ANIMALCULA OF INFUSIONS, LF are fome that die very foon after privation of air, others after a longer interval, and the length of it is according to the nature of the animalcula. A fparrow, a nightingale, and in general other birds, quickly die in vacuo. A lizard, a frog, or a reptile, remain fome time alive ; infects, ufually much longer. As there are diftinctions among infufion animalcula, there is a difference in their ability to fupport a vacuum; and thofe that do fo longeft, feem of all animals, the moft capable of living without air, at leaft we are unacquaint- ed with any fpecies that exift a month m_ that {tate, as we have feen fome animalcula do. Though they can long fupport privation of air, they at laft fink under it and die, which is proy- ed by the animalcula living in the open air above two months. And this confirms the general rule, that all animals require air. I know there are inftances given of fome which are faid to have lived without this element ; fuch as the famous {tories of frogs found alive in the middle of the hardeft fubllances, and living toads difcovered in the centre of ftones, or of entire trees, where not a particle of air could penetrate into their hidden receiles(i). But I am alfo aware, that fuch hiftories are more the object of the admiration than belicf of perfons who have made any progrefs in experimental philoiophy ; becaufe, they (1) Melanges d’Hiftoire Naturelle. L ANIMALCULA OF INFUSIONS. 117 they are not corroborated by that authenticity which is effential in a cafe fo ftrange and para- doxical, more efpecially as the pulmonary {tructure manifefts that they are adapted for refpiration. Therefore, until facts are produced to the con- trary, more credible and better proved, we have fufficient reafon to affert, there is no living ani- mal in nature, limiting ourfelves to thofe already known, that can exift without the benefit of air (1). H 3 CHAPs (1) There are numerous accounts, unqueftionably very fingular, of animals found alive in folid maffes; and fe- veral intelligent and reputable perfors have gone fo far as to affirm that they have feen them. It is very difficult to conceive how an animal formed for breathing can live deprived of air: but it feems little lefs difficult to reject the teftimony of the moft creditable men. Every day, we dif- cover new fingularities, which would be abfolutely incre- dible without authentic information. This is a fa@ in which mote than ufual evidence is required ; for without that, nay, without ocular demonftration, we find it in- comprehenfible. Yet 1 can never underitand why the toad. is almoft always felected for thefe wonderful prefervations, and feldom any other animal. ‘There is an extract from a Jate Memoir on the fubje& by Murhard, Philofophical Ma- azine, Vol. 3.—Ts 118 ANIMALCULA OF INFUSIONS. 1, CHAP. VII. SINGULAR MODE IN WHICH MANY SPECIES OF ANI- MALCULA PROPAGATE. Ty we obferve two animalcula united, the firft idea which arifes is, that they are occupied in the work of generation; and we cannot avoid it, though the animals exciting the idea are infinitely minute, becaufe uniform example proves this to be the ufual pofition of animals for propagating the fpecies. Hence the actual copulation of animal- cula has been fuppofed from feeing them united in pairs. Such is the opinion of Ellis, and the celebrated Father Beccaria, as he informs me in a letter, written many years ago, concerning my firft obfervations on infufion animalcula. The whole is here tranfcribed, as it is particular on this phenomenon, and alludes to other important points. 7 Turin, 11 September. 1765. ‘If your excellent experiments required any © fupport from the teflimony of another, I could ‘ afford it: for, twelve years ago, when the Duke ‘ of Savoy called me to fee Mr Needham’s ex- ¢ periments on microicopic animals, I thought it ¢ my 1% * ANIMALCULA OF INFUSIONS. 119 ‘my duty to prefent him a long treatife with this © motto, Si parva licet componere magnis,—in © which I demonftrated, from analogy, the fallacy * of the opinion advanced ; and then pointed out, ‘ that it was not the confequence of experiment. © Befides, I employed moft of my leifure hours, * for two years, in experiments on what feemed © fo interefting a fubject ; and fucceeded in dif- ‘ covering, 1. How infufions diffolved the fixed ‘falts of the fubftances, carrymg them to the * edge and diflipating the volatile part, ‘as is evi- * dent by the tafte and fmell, and leaving a gela- *‘ tinous matter well adapted to collect and feed ‘animalcula; 2. That animalcula have a proper ‘ internal and fpontaneous motion, in addition to ‘ the characteriftics of avoiding obftacles, chang- ‘ ing their diretion, and pafling above them ; alfo, ‘ the two following, thus defcribed in my Treatife, © Lucem refugiunt, paulo vividiorem, putrem ma- * teriam appetunt, quaft ut vefcantur. A fingular fa&t, relative to the multiplication of animal- * cula, cannot have efcaped your penetration. I “have often remarked, that at full fize they ‘ feemed in copulation. ‘Two animalcula are fre- © quently feen at the circumference of a drop of ‘ putrid matter, one fupported by a. particle or * joined to it, or, to fpeak more certainly and ‘ adhering to appearances, in contact with it, and € continually vibrating or ofcillating in the direc- H 4 © tion 120 ANIMALCULA OF INFUSIONS. L tion of a ftraight line uniting the centres of the two bodies; and the ofcillation is particularly manifefted. by the motion of fome internal parts ‘near the line of direction. But fome referve has probably induced you,. as well as myfelf, to be filent concerning this moft fimple obfer- * vation.’ In my anfwer to the polite and learned let- ter of this celebrated philofopher, I had the hon- our to inform him, that I had feveral times feen the phenomenon of two animalcula united, which was exprefsly mentioned in my Journals,—and had even fketched the figure; but, to confefs the truth, although it did appear that this union might be a real copulation, I could not refolve to advance it in my Differtation from the fear of being deceived. Animalcula are a part of the creation as yet little known to philofophers ; and it is eafy to be miftaken by applying our ideas of large animals to'them. ‘Thus was I induced to leave the matter in obfeurity ; and only defirous that fome more fortunate or more acute obferver would promote the interefting fubject, on which’ my poor abilities had thrown any additional illuf- tration. Happily my wifhes were not vain. My obfervations came into the hands of M. De Sauf- fure, who, among other phenomena, having fallen on this fuppofed copulation, made it the fubjec of leng, nice, and minute difcuffion ; and y. ANIMALCULA OF INFUSIONS. FIT and he at laft difeovered, that it was not the co- pulation of two animals, but one animal which multiplied by a divifion into two parts. His ob- fervation was communicated to M. Bonnet, who tran{mitted it to me. My Solitude, 27 “fanuary 1770. ‘I have hazarded fome conjectures on infufion animalcula, and their mode of multiplication, “in the firft volume of my Con/fiderations fur les © Corps Organisés, chapter 3.; and it is there ‘faid, ‘* Let us prefer conjectures founded on ob- “< fervation or experiment.—Let us compare thefe *¢ animalcula to polypi, and other infects, multi- “plying by fections.—Let us fuppofe they pro- “* pagate by natural divifion, fimilar or analogous * to the clufter polypus ; or, by breaking or fe- “‘ parating with extreme facility, like the frefh “¢ water anguillae, fpoken of in my Traite “* d*Infectologie, Obfervat. 21. part 2. By fuch *« fuppofitions, we may explain the chief pheno- **‘ mena prefented by animalcula—that fingular “ diminution of fize and encreafe of number.”’ ‘I do acknowledge, that I had no great hopes ‘that thefe conjectures would one day be veri- “fied, nor was I very fanguine in their favour, ‘ Animatlcula are fo minute, that it was not eafy “to prefume the myftery of their reproduction ‘ would be inveiled. But it is now accomplifhed ; ‘and we owe it to a.naturalift, who, although * experienced i nr an “an a) wn May wn n Va) “ a a bal 4 € € € 24 ANIMALCULA OF INFUSIONS. 1 experienced in the rare and uncommon art of interrogating nature, is reftrained by modefty from making his difcoveries known, left they may not be fufficiently comprehended. A work containing excellent obfervations on the Petals of Flowers, a fubject but little underftood, has already fpread his name among the limited number of his equals. It is evident I mean M. de Sauffure, who, at an age when men only be- gin to think, already fills one of our philefophi- cal chairs with credit. His affectionate attach- ment to me, which is merited but by a recipro- cal fenfation, would not permit him to let me remain ignorant of his difcoveries concerning the mode of animalcula propagating. ‘Thefe are re- lated at large in the following letter, which well deferves the attention of obfervers (1). “© Geneva, 25 September 1769. “¢ You have great reafon, Sir, to fuppofe, that *‘ animalcula of infufions may multiply by con- “ tinual divifion and fubdivifion like polypi. You “* {tate it only as a fufpicion ; however, my ob» “¢ fervations, on many f{pecies of thefe fingular ani- “mals, convince me that we may regard it as a *¢ fact. Animalcula of aroundifh form, without “<< beak, (1) This and M. de Sauffure’s letter are inferted in the republication of La Puiingenefie. ~ te ANIMALCULA OF INFUSIONS. 12% «beak or hook, divide tranverfely in two. A « contraction appears at the middle, which gra- “ dually increafes until the two parts are attach- *¢ ed only by a thread : the animal, or rather two «¢ animals, make violent efforts to complete the 4 {eparation ; and, after it is effected, feem ftun- *< ned for fome feconds. They afterwards. begin ** to traverfe the liquid as the entire animal did. “ You will eafily conceive, that, in the firlt ** movements of their new life, they are {maller “¢ than the animal they compofed, each, in reality, * is only one half, but it foon acquires the fize “‘ of the whole, and, in its turn, divides into €¢ animalcula that rapidly become equal to it. ‘¢ Mr Needham has done me the honour te “commend this obfervation in his notes on the “ tranflation of Signor Spallanzani’s excellent “ performance ; and employsit in fupport of his *¢ theory, which is, that the fmalleft animalcula of “¢ infufions, thofe that feem points before the moft “ powerful microfcopes, are produced by continu- < al divifions and fubdivifions of the large fpecies. “ Undoubtedly, in four years which have elapfed “ fince | communicated this obfervation, he muft *¢ have forgot that I conftantly obferved the “ parts of the divided animalcula in a fhort time “became as large as the whole to which they “had belonged. Therefore, in their propaga- “‘ tion, we find the fame conftancy and unifor- * mity that is feen in the reft of nature. Per- * haps ¥24 ANIMALCULA OF INFUSIONS. ir * haps I did not infift with Mr Needham on this “ peculiarity ; perhaps I did not inform him ‘that, to remove every poffibility of doubt, I “ put a fingle animalcule in a drop of water ; “‘ that it divided in two before my eyes; that “* next morning thefe two had become five, and, “ during the day, fixty; and on the third day “¢ were fo numerous, that it was impoffible to « count them; and all, except thofe juft produc- “¢ ed, of equal fize to the animalcule from which *< they came, “© When, for the firft time, you fee the animal “ dividing, you will think it the copulation ‘of two. I was completely deceived ; and “‘ thought, like Micromegas, that had caught “nature in the faét: nor was I undeceived <‘ until one had, in the fpace of twenty mi- “ nutes, fucceflively paffed through all the de- “¢ erees from the moft imperceptible contraction “< to full feparation (1). <¢ What is moft remarkable in the inftin& of « thefe animals is, when they obferve or difcover ** two (1) Muller ingenuoufly acknowledges, that the firk animalcula he had feen united feemed to him in copula- tion: and this feductive phenomenon may impofe on any one; whence Father Beccaria’s innocent miltake was not furprifing : and there is no doubt that he would have dii- ecvered the truth, if his refearches on ele¢tricity, which do him fo much honour, had allowed him time to profecute the obfervations J. ANIMALCULA OF INFUSIONS, I2¥ ** twoon the point of feparation, and exerting ‘* themfelves to attain it, they precipitate them- *‘ felves between them as if to affift in break- “ing the connecting ligament. Nor can we * view thjs act as only fortuitous, fince they are “< generally careful to avoid one another, and “* never ftrike together whatever the rapidity of “< their courfe may be. *¢ Another fpecies, found in hempfeed infu- “¢ fions, wich a beak or hook before, alfo multi- ** ply by divifioa, but in a more fingular man- “ner. When going to divide, the animalcule “* feeks a convenient place at the bottom of the ‘* infufion, commonly that femi-tran{fparent kind *< of mucilage which forms in hemp infufions. “* After fearching and examining various places, “it at laft fixes on one. The body, which is * naturally long, contracts, the curved beak is “ retracted or concealed, and the animal af- ** fumes a fpherical form: it next infenfibly be- os gins to revolve on itfelf, fo that the centre of ‘¢ motion is fixed, and the fphere never changes ‘its place. ‘The motion is performed with the *‘ moft perfect regularity, but the direction of “ rotation is conftantly changing, fo that the ro- “‘ tation may be firft from right to left, then «¢ from before, and next from left to right. And << all thefe changes are imperceptibly performed, *‘ without the animalcule or rotatory machine ** changing 726 ANIMALCULA OF INFUSIONS. i. «¢ changing its place. At length the motion ac- * celerates; and at the point where the fphere *¢ feemed motionlefs, two crofs divifions begin to _ be vifible, exaétly like the hufk ofa chefnut << ready to burft. Ina little longer, the animal “ appears agitated, and making great exertions, < and at laft divides into four, the fame as the “¢ producing animalcule, but fmaller. Thefe <¢ srow larger, and each divides into four, which, << in their turn, increafe. I could fee no end to “the fubdivifions; the young always became << equal to their parents, if we may ufe the word *¢ parent in this fingular mode of generation.” M. Bonnet adds the following words: ‘In ¢ the laft fpecies of animalcula is another analogy “with clufter polypi evident: We know that ‘ thefe create a little vortex in the water, which € precipitates the food towards their mouth. Our “animaleula perform a fimilar operation, and ‘ furely with the fame intent.’ In this new courfe of experiments, I have had the advantage of examining M. de Sauffure’s dif- covery, to verify and extend it, and find, that befides the fpecies he obferved, there are many others which propagate by a natural divifion, but often in the moft fingular and unaccountable manner. We may begin with the fimpleft; and firft with the tranfverfe divifion, bemg that mentioned by the Genevefe profeffor. It fuc- ceeds i ANIMALCULA OF INFUSIONS. 129 ceeds both in {pherical and elliptical animalcula, and in fome other fpecies without either beak or hook. For the purpofe of correét obfervation, I ifolate an animalcule in a watch-glafs. If the weather is warm, traces of contra¢tion are vifible about the middle of the two fides; it infenfibly advances; and the animalcule fomewhat refembles a blown bladders tied tight acrofs. . It {till fwims about, darting its head among the particles of matter, if any are in the glafs. The contraction continues increafing ; and the animalcule is at laft changed into two fpherules touching in one point, Plate 1. Fig. 1, ABC. TYhefe conne@- ed ipheres continue moving as the entire animal did, but they often ftop. ‘Vhe pofterior fpherule feems to be carried on by the weight of the ante- ior, and appears to have no fpontaneous motion of its own, but what is neceffary for feparation from its companion. This at length is done, and of one animalcula, two are formed. At firft, they are apparently unable to move; however, each foon refumes the velocity of the original whole. ‘The fpherules in time acquire the fize of the entire animal. Though all the {pecies dividing tranfverfely feparate into two equal halves, thefe parts are not uniformly fpherical, but more or lefs elliptic when very near divifion: Nor are the new ani« malcula always torpid and inactive, for they of-. ten «28 ANIMALCULA OF INFUSIONS. i ten retain the former velocity of the compofing whole. It particularly merits obfervation, that the fize of the two animals, while actually dividing, is fo much augmented, that each is almoft equal to the original, of which I have had undoubted evi- dence, by comparing each portion with one en- tire of the fame fize and fpecies as that divided. The animalcula from thefe divifions being alfo ifolated, fimilar young are continually produced by divifions and fubdivifions. Among thofe dividing tranfverfely are fome generations, (like the elliptic kind, pointed be- fore, fometimes originating in wheat infufions, and rather large) whofe anterior part is provided with fhort fibrilli in conftant motion. The vor- tex afcribed by M. De Sauflure to the fecond fpecies of his animalcula, is certainly produced by this motion (1); but acute vifion and a pow- erful magnifier are neceflary to difcover the vor- tex and fibrilli(2). Neither the vibration nor vortex (1) Muller, difputes the correétnefs of this obfervation. Vortex, quem animalculum, cujus meminit, claris. Sauf- fure ex infufione cannabis, partitioni intentum ciet, non, uti autumat illuftris Spallanzani, vibratione pilorum, cum iis careat Kolpodeque generis fit, fed totius corporis i tioni debetur, Animal. Infus. p. 246.—T. (2) There are few microfcopic objects fo difficult to difcern accurately as the vibrating fibrilli of fome animal- ula. Their extreme minutenefs, their continual motion and {: ANIMALCULA OF INFUSIONS. 129 " vortex is interrupted, during the divifion of the animalcule ; and both continue when it is finith- ed. After feparation, the pofterior part acquires the filaments ; and, in a fhort time, alfo produces a vortex: I have counted fourtecn {pecies of animalcula multiplying in this manner: only two merit de- {cription: We fee a kind of circular animalcula, above the middle fize, in infufions of bearded wheat: From the circumference of the body arife a circle of minute protracted points fimilar to very flender cones, and in the quickeft mo- tion. This animalcule and its points are men- tioned in my Differtation; but for want of the néceflary obfervations, I was uncertain of what ufe they might be (1); Now, I do not think my- felf deceived in fuppofing that they ferve for fwimming, as the fins and limbs of fo many other aquatic animals. This is deduced from two rea- fons ; firft; becaufe the points are at reft while the animal is tranquil, from their motion when it moves, and the accelerated vibration when at its greateft velocity. Secondly, if, by any acci- dent, the number of points is diminifhed, the ani- Vor. Tf: I mal and removal from the focus of the microfcope, render it a nice and delicate matter to bring them diftinétly into view. —T. “ (1) Capitol. 2. 130 ANIMALCULA OF INFUSIONS. t mal no longer moves, or does fo very flowly- Propagation is operated by a tranfverfe divifion — in two. The feparation is. flow, and attended with one fingularity, that, before being fully ac- complifhed, each portion is as large as the whole, and, in the place of divifion, has acquired points fimilar to thofe of the old animal, but fhorter. The other fpecies, which muft not be overlook- ed, is found in an infufion of marfh-lentil, and is fometimes fo large as to be vifible without the smicrofcope. By filling a thin fided chryftal tube, and placing it in the fun, the animalcula are fo confpicuous to the obferver’s eye, that the fuc- ceflive divifions may be eafily feen. Other ellip- tic animalcula are obferved with the contraGion fcarcely begun, fome with it far advanced, and others with it almoft completed. The multipli- cation is fo abundant, that a fingle animalcule, at certain times at leaft, will, in a few days, people a whole infufion. It have ftill to fpeak of longitudinal divifion, for that is alfo a way in which animalcula propa- ‘gate. Thofe with the filament, already mention- ed, divide longitudinally ; but the eafier to un- underftand how it is effected, we mutt firft de- . {cribe the animalcule. On prefenting a drop of —infufion to the microfcope,. animalcula are feen among the vegetable fragments, fome attached to particles of matter, and others wandering free- _ ly > —— Jj; ~ OANIMALCULA OF INFUSIONS. “138 ly about in the drop. The filament proceeds from the pofterior part of the animal; and al- though its natural pofition is in a right line, it often contracts fuddenly into a fpiral whofe volu- tes approach fo near as to touch: in a moment they recede; the fpiral unfolds, and refumes the {traight line. While unfolding, or already ftretch- ed; if a gentle motion is given to the drop, the filament becomes a fpiral. If its extremity is fixed, any contraction towards the fpiral forces the animalcule rapidly to the fixed point; when free; it approaches the animalcule. ‘This it fre- quently does, almoft periodically: It is of a pearl colour; and of extreme flendernefs, at teaft compared with the animalcule; the length equals it, and is fometimes more. The figure refembles an onion or bulb: to the extremity is attached the filament as the roots originate ; thence it was named the bulb-animalcule(1). A circular row of filaments proceed from around a hollow. Thefe extremely flender fibrilli are in a conftant vibratory motion, which occafions a whirlpool in the fluid, abforbing the fmalleft adjacent particles, and fometimes very minute animalcula. As the bodies gradually approach, the motion becomes more rapid. Attending I2 carefully ms 1) This is the Vorticella Hians of neice. Animale bula Infuforia, p. 321.—T. 132 ANIMALCULA OF INFUSIONS. 1p carefully to the fibrilli, it is not difficult to account for the operation. After the largeft fubftances enter the hole or hollow of the animalcule, they are rejected, but the fmalleft remain ; and there is every reafon to believe they penetrate the body by fome invifible channel. The intent of the operation is in all likelihood for the animals nutri- ment and prefervation; the vibrating fibrilli caufe a vortex ; the vortex draws in the floating particles; and the animalcule felects either the moft delicate or what fuits it beft for food. Befides the periodical motions we have afcrib- ed to the filaments, there are others peculiar to: the animalcule. Whenever the filament con- tracts, the animalcule alfo contracts, fuddenly concealing the hole and fibres within its body, and affumes the figure of a fpherule, D. pl. 1. fig. 2: Ina few feconds, the filament is extend- ed, and the animalcule becomes like a pear, E ;. then its ordinary fhape outlined F, and finifhed G: The fibrilli and hole re-appear ; the vortices. recommence when their motion begins, for there. is an entire ceffation while the animalcule remains. contracted within itfelf. I firft faw thefe animalcula dividing in two in: an infufion of white kidney beans boiled twe- hours. ‘The anterior part of one feemed lan-. guid, which induced me to fufped it was going to divide. Two mifhapen animalcula, attached: by. q. ANIMALCULA OF INFUSIONS. 133 ‘by many points, appeared: each had its appro- priate fibrilli and confequent vortex. Befides the ufual contraction and extenfion, the animalcula were full of agitations and contorfions, and al- ‘ways feparating more from each other, chang- ing their mutual pofition, until the two holes and vortices became diametrically oppofite.—The fe- paration advanced ; and in half an hour from the firft obfervation, they were connected only by a point. The filament, which during the whole time of dividing periodically contracted and ex- tended, was no longer common to both animal- cula, but belonged to one whofe only motion ‘was vibrating the fibrilli, retra@ing them, and extending itfelf. ‘On the contrary, the other ani- malcule was occupied with bending into different forms, in contorfions, and revolving on its own axis. At laft it feparated from its companion, began to fwim in the liquid, and very foon left the field of the microfcope. This obfervation was a rule for experiment on many more of the fame {pecies ; and I uniformly obtained the fame refults by ifolating them in watch-glafles. A little cleft was feen at the an- terior part of the animalcule, dividing the hole afunder. The cleft encreafed; the vortex be- came double; and each portion acquired the rude figure of an animalcule. ‘The feparation advan- ced; the fhape grew more perfect ; and divifion rs being 134 ANIMALCUSA OF INFUSIONS. i being almoft completed, they were tranfmuted into two entire and well formed animalcula. One remained attached to the filament, and, in a fhort time, became as large as the whole, and, by new divifions, gave birth to new animals. The other had no filament, it rapidly traverfed - the fluid, contracted, extended, and an appen- dage foon budded from the pofterior part, which was the rudiments of the filament. With this the animalcule fixed itfelf to fome furrounding | fubftances : the filament lengthened, and the ani-- malcule began to divide again. In fig, 3. pl, 1. are the various degrees of divifion. | Thefe animalcula fometimes perifh when ifo- lated in diftilled water ; and the like may be faid of all that divide : however they often divide and fubdivide, ftill their glaffes are never populous ; but the numbers encreafe exceedingly, if portions of vegetable matter are mixed with the diftilled water. Privation of food in the one cafe, and abundance in the other, is undoubtedly the caufe of this difference. Bulb animalcula not only inhabit boiled but alfo unboiled infufions of kidney beans, and ma- ny other legumes, as lentils, beans, and peafe. No- thing more is required for the convenient obfer- yation of their propagation than to macerate a few particles of feeds. . In two or three days, if the experiment is made in fummer, fome animal, | cula I. ANIMALCULA OF , INFUSIONS. 135 cula are feen attached by the filament to minute ‘fragments in the infufion ; and they will divide before the obferver. The number fixed by the filaments is proportioned to the number of divi- fions about to take place. The fame legumes produce another fpecies of animalcula, alfo multiplying by longitudinal di- vifion, and prefenting phenomena fimilar except in two facts: fir/?, The fibrilli are not in the ca- vity, but on its lips; /econdly, The figure refem- bles a monopetalous flower. The body divides exadtly in two. There is alfo a fpecies confiderably larger, which propagates by a little fragment detaching itfelf obliquely from the body. This animalcule is fometimes found in an infufion of beets. It is {pherical, and has a filament which is not en- dowed with the fingular motions of the other two fpecies, nor is the body fubje& to thofe mu- tations of figure. The multiplication begins with a {mall portion infenfibly detaching itfelf from the body, near to the origin of the filament, and it is in continual motion, Plate 1. fig. 4. H. When feparated, it fwims actively through the fluid; and although fmaller than one-twelfth of the whole, it becomes equal to it in lefs than a day. Then it begins to propagate in the fame "manner. I 4 As . 136 ANIMALCULA OF. INFUSIONS. 1. As I have repeatedly fpoke of ifolating sli malcula, or the method ufed of confining one in a watch-glafs, on purpofe to obferve the fuccef- five degrees of divifion, the reader will naturally be earneft to learn the mode employed, much. more fo if he 1s accuftomed to fuch matters, and knows the extreme difficulty of obtaining one alone in a drop of infufion, however fmall. Sauffure himfelf. {tates it as exceedingly difficult, and that by dint of patience he fucceeded in con- fining one in a drop of water ; and I muft con- fefs it was a great labour before I fell on a ready method. A drop of infufion is conveyed into a watch-glafs with the point of a pen; it is of na confequence although abounding with animalcu- la: a drop of water is put two or three lines from the firft, and they are made to communi. cate by a little channel formed by drawing out the circumference of the drops. The animalcula are not flow in traverfing the channel, and arrive one after another in the drop of water. » Obferv- ing this paflage with a magnifier, whenever I fee an animalcule enter the water, I cut off the com- taunication with a hair pencil: thus imprifoning a fingle animalcule. If more than one are to be confined, it is ealy to allow any number to enter the drop. ‘The infufion being then taken away, only one remains in the watch-glafs, or more if I choofe it. 4 1, ANIMALCULA OF INFUSIONS, 139 I fhall here fpeak of an objection ftarted by Mr Ellis, lefs becaufe it merits refutation than becaufe it fhould not be entirely overlooked. His opinion is, that the divifion of animalcula is not a natural mode of propagation, but the effect of accident, and that it is occafioned by accidental fhocks, from ftriking again{ft each other. This opinion he deduces from two reafons; firft, from the proportion of animalcula dividing to thofe that do not, which is fcarcely as one to fifty ; and, fecondly, from obferving young in the body of adults, and within the young fome {till youngs er (1). : It was unfortunate that M. de Sauffure’s dif- covery had not been publifhed when this learns ed naturalift compofed his Memoir. Had he feen his obfervations, and what has fince been obferved by me, it is no arrogance to affirm, that he would have deeply penetrated into experimental refearch on infufion animalcula. He would alfo have perceived that the fhocks and {triking together are perfectly imaginary. In theend of my Dif- fertation, their anxiety to avoid one another, and different ob{tacles, are mentioned in exprefs terms. The like is remarked by two excellent naturalifts, Father Beccaria and M. de Sauflure ; and, in my new enquiries, I have had opportunities of fecing the fact confirmed a thoufand times. Theretore, it {1) Philofophical Tranfastions. 138 ANIMALCULA OF INFUSIONS. f. it is falfe that the divifion of animalcula is the effect of mutual fhocks: and if that fpecies, which the Genevefe naturalift mentions, feems to prove the reality of the fhocks, it is not at the beginning, or when farther advanced, but when the divifion is almoft at an end, and then only, that any fhocks are given by the companion ani- malcula, and when the dividing ones are exert- ing themfelves to feparate. Befides, their inftinct to aflift in feparating appears peculiar to this fpe- cies. -I have never witnefled any thing fimilar in the numerous kinds examined. But the experi- mentum crucis again{t Ellis’s objection is, that ani- malcula, ifolated in glaffes, multiply by divifion | as the reft, though they can experience no fhocks from others. Had my refpectable colleague continued to fitudy animalcula, he would have perceived the infufficiency of the proportions he has given from the immenfe numbers in actual divifion. Fre- quently among innumerable multitudes traver- fing an infufion, there has hardly been one that - did not exhibit figns of divifion. But I can comprehend what has mifled Ellis.” By con- ftant obfervation, I find that this mode of multi- plication has determinate periods ; at one time, it cannot be more general; at another, it is rarer ; and now it is not to be feen at all. Ap- parently, his obfervations were made when the propa- lL ANIMALCULA OF INFUSIONS, 13g 7’ propagation was about to end; thence was a pro- portion aflumed which he fuppofes general. [f cannot think myfelf deceived in conceiving this has mifled the author, as he mentions having dif- covered the young and their defcendants in the bodies of the old animalcula. Many of thefe animals appear to be tranfparent folliculi, with veficles or grains internally {trewed here and there, very often cluding others {maller. The firft time of obferving animalcula, we are ea- fily perfuaded that thefe veficles or granuli are young. Many perfons prefent at my obfervations were of this opinion; and I cannot deny that I was of the number. But in truth they are not animals, which I can affirm from the moft cer- tain and indubitable proofs. Several animalcula were iolated in a watch-glafs; and that they might be all in the field of the microfcope after the number had increafed, a little water was al- ways left in the glafs. Thus fome individuals might be felected and recognifed. The granuli themfelves aided me to this, becaufe they are feldom or never in the fame pofition in one ani- malcula as in another: {fo it was eafy to obferve whether they aCtually underwent any change. But the number never diminifhed ; they remain- ed invariably the fame during the whole period of my examination; and at laft had increafed emazingly. ‘Thus the granuli have no part in . the {40 ANIMALCULA OF INFUSIONS. L the propagation; and we muft admit that they are intended for fome other ufe, though to us un- known. ‘The whole fubftance of the arm polypi, which multiply by divifion, is alfo granulated ; and M. Trembley has demonftrated, that thefe grains have no fhare in the multiplication. In the extenfive empire of animalcula, natu- ralifts are acquainted with one fpecies only, as far as I know, which multiplies in the manner Ellis defcribes. This is the celebrated volvox, apparently fo named from revolving on itfelf in its progreflive motion, firft difcovered by Leeuwen- hoeck, and then found by other naturalifts. From the great tranfparency, like moft animalcula, the mternal ftruture is clearly feen; and fome obfer- vers have already difcovered the young within even to the fifth generation. In my long obfer- vations on infufions, I have found two particu- larly abounding with the volvox, hempfeed and tremella. There are often many in the putrid water of dunghills. Thefe animals are originally very {fmall, but grow fo large as to be percepti- ble by the naked eye. They are of a greenith yellow colour, a globular fhape, of a very tranf- parent membranaceous fubftance, and ftrewed with the moft minute globules within. Three volvoxes of different fizes are reprefented, Plate 1. fig. 5. Examined with a very powerful mag- nifier, thefe globules are difcovered to be fo many t ANIMALCULA OF INFUSIONS. ‘4% many volvoxes infinitely more minute; and each provided with its diaphanous membrane. I have been able to difcern the third generation, but never the other two, though I had recourfe to. magnifiers of the higheft power. Perhaps it was not my fortune to recognize them, or they were not vifible in the volvoxes examined, from a dif. ference in the fpecies and fize between them and thofe obferved by other naturalifts(1). It is un« doubted that globules within globules are fo many generations included within each other; for when my volvoxes had attained a certain ma- turity, the {maller globuli began to move within the membrane, detached themfelves from it, left the mother, and fwam in the infufion, revolving on their axis, and in this manner pafling along according to the mode peculiar to thefe animals. When all had come forth, the common mem- fee or mother, burft, and diffolved; and hav- ing loft all motion, I loft fight of it alfo. In the meantime, the new volvoxes increafed, as the-in- cluded globules likewife did; thefe began to. move, the common membrane burft, and they fwam about in the infufion like the former. By iolation (1) Muller, who defcribes feveral {pecies, has feen only the young and its offspring in the body of the mother, and that but in a fingle {pecies which he calls volvox Bla bator. x4e ANIMALCULA OF INFUSIONS. hi ifolation in glaffes, I came to have the thirteenth generation in fucceffion. . Here I muft be allowed to make a digreffion: One of the ftrongeft objections to the theory of germs, is the great difficulty of conceiving the fucceflive envelopement of animals in animals, and plants in plants. It has been attempted to obviate this objeCtion, by ftating, that it is more adapted to f{tartle the imagination than to confound reafon, which admits of the infinite divifibility of matter, and examples favourable to envelope- ment have been adduced to weaken it. One egg has oftener than once been found within another; _ and fome offeous parts of one foetus included in another foetus(1). The butterfly is firft includ- ed in the fhell of the chryfalis, and the chryfalis in the {kin of the caterpillar. In vegetable feeds are found the rudiments of the future plant; and the fourth generation has been feen in a hyacinth root(2). The volvox affords a new and beau-» tiful inftance of envelopement; the eye has been able to fee the thirteenth generation: probably that is not the laft. I cannot {peak otherwile, fince nothing but time was wanting to inveltigate whe- ther further developement would appear. But the naturalift is invited to extend this moft im- portant obfervation. Baker, (1) Hiftoire de L’Acad. Roy. 1742, 1746, k (2) Bonnet, Corps Organifes, tom. 1. % ANIMALCULA OF INFUSIONS. 14% Baker, in his Treatife The Microfcope made Eafy fpeaking of the minute and innumerable creatures: inhabiting waters, mentions a race of animalcula difcovered by Leeuwenhoeck in the marth lentil, remarkable for a long tail, with which it attaches. itfelf to the roots of the plant, and:a_ hollow like a bell in the anterior part of the body ; it is alfo characterized by a fpontaneous motion, contraé- ing and extending the body and tail at pleafure. Thefe fingularities, fo analogous to thofe of my ‘bulb animalcula, excited the defire of feeking for what was to me a,new kind of animal, to learn ‘whether its multiplication was by natural divifion. But as it often happens, the more one feeks a thing the lefs ‘\does he find it; and when leaft thinking of it he difcovers it, or rather it feems to find him ; fo was it with Leeuwenhoeck’s animal- cula. When I gave myfelf much trouble and folici- tude I never was able to difcover them ; and they at length appeared when I was occupied in matters. entirely different. Intently confidering fome tad- poles about the roots of marfh lentils, which had been put into a vafe of water to feed them, and the diredt rays of the fun falling on the water, I faw the roots very diltinly, and diftinguifhed ene from the reft by a light {pot of fhining white,, {urrounding it about the_middle of the length. This peculiarity did not make the fmalleft im- preffien is 8 144 ANIMALCULA OF INFUSIONS. t preflion on my mind at firft, but it was foon evi- dent that it difappeared in a few feconds, and in’ a little appeared again, which feemed to be perio- dical. While the tint was vifible, I gently took away the radicle; it fuddenly vanifhed ; but, the fhock having abated; unexpectedly re-appeared. The fingularity of the. phenomenon recalled to my memory the animalcula of the marfh lentil. Examining the fpot more narrowly, I faw, with — extreme pleafure, it was a group of more than fifty tails of the animalcula, the extremity of which was fixed to a lentil root: Thefe ani- malcula refembled the bulb f{pecies, not only in extenfion and contraction of the body and tail; but in generating a vortex and directing the float- ing particles into the hollew or bell, by means of a circle of filaments or points, proceeding from the edge of the bell, Pl. 1. fig..6; As this fpe- cies is much larger than the bulb animalcula, fo are the points and vortex proportionally larger. If the bell was wide open, which happened when the animal was extended, it feemed to terminate in the body by a httle central hole, I. I tranf: ported this family of animalcula with the lentil root into a watch-glafs, for more convenient ex- amination. ‘They remained feveral days with- out appearing to multiply. At length all perith- ed; the animalcula were untwined ; motion ceaf- Ing, I. ANIMALCULA OF INFUSIONS. 145 ae ; ing, the filaments ceafed to move, and then the tails (1 ). It may well be fuppofed, that fimilar groupes were eagerly fought on the fame plants; but in ‘vain. However in fix days, I had the fatisfaction to fee a new fpot formed on one of the roots, I fay formed, for it certainly was not there before ;. as it was much larger, the animalcula were more numerous. They and their tails performed -the, wonted reciprocal extenfions and contractions even when untouched, and the water at perfect reft ; thefe motions diminifhed or augmented the fpot. The whole could not be brought into the field of the microfcope from their . prodigious number, I therefore took. away a confiderable part, and, excluding a large halt, referved a por- tion for examimation, adapted to the capacity of the inftrument. New fingularities occurred. The portion reprefented.a tree in miniature; number- lefs branches, dividing into fmaller ones, pro- ceeded from the trunk; thefe into others fuccef- fively lefs ; and each of the {malleft bore a bell amimalcule at the extremity. No fcene could be more uncommon or more agreeabie. Every three or four feconds the trunk unexpectedly contrac- ted towards the lentil root, and initantaneoully Vo. [. i drew (1) Muller calls this the Vorticella Convallzria. Animal. dnfuf. p 315.—T. * 146 ANIMALCULA OF INFUSIONS, I. drew in all the rages: twigs, and animalcula,, _ but in a moment reftored the tree complete, with — all its animals, to the original flate. ‘The reader will eafily comprehend, that a vegetable is not meant undér the appellation free, becaule it is evident from itfelf, that it is an entire aninaly, which cannot be better figured than by the re. prefentation of a tree. As Aa animalcule formed its own vortex, and there being above an hun, dred, the appearance of fo many whirlpools at qnce prefented a molt fingular and interefting ipectacle, elpecially when highly magnified wae the folar microfcope. I detached the fhrub from the lentil root, ‘by. - cutting through the trunk. ‘The fcene changed, but, to one equally pleating. The animals, branches, and twigs, no longer approached the flem, but the ftem, twigs, and branches were “{uddenly carried away by the animals; and at this inftant all the w nirlpoale difappear ed. Amidft thefe alternatives, the, animalcula, no longer fixed to the root by their trunk, fwam flowly through _ the fluid, drawing along the plant and its branch- es; and, while this common motion continued, | the various parts of the plant alternately ap proached and receded from the animalcula (1). Having (1) I I cannot afirm that I perfealy comprehend the A Luthor’ s deicription.—T. 4 d . 2 i ANIMALCULA OF INFUSIONS. 147 Having left the plant thus in the glafs, I ex. amined it next day; all was in the fame fate, except that inftead of one animalcule as before, proceeding from the extremity of each branch, there, were two, Plate 1. fig. 7. K. And thofe yet fingle were marked with a very fine furrow, L. The novelty attracted my attention; and it was foon perceptible that the furrow indicated an incipient divifion; each in a fhort time be- came double. Then I began to underftand how fo many animalcula appeared double on: one pe- dicle; it was a propagation from divifiom: I can- _ not fay whether the origin of the branches, to which they are attached, feparate in® the fame manner; my obfervations on that fubject have _ not been fufficient; but the animalcula were in pairs, and thofe at firft almoft in contact, in half a day, were far afunder, and had attained their complete fize, K. L. fig. 7. plate 1. Fur- ther, I can affirm, that from each old branch two new ones budded; and the reproduced animals were implanted on their fummit, K. Thefe at. tained the neceflary fize, divided as the parent, _and remained to terminate new branches or twigs ; whence the multiplication of branches “was in proportion to that of animalcula, and both continued multiplying many days(1). Kg : During (1) Muller feems to confider this a diftin@ {pecies from the former, and names it Vorficel/g Pyraria. The defi- | nition » Wei: 148 ANIMALCULA OF iNFUSIONS: © ie During this the branches of the fhrub hal fa. much extended, and become enlarged, that the. circumference was triple. But the fupervening death of the animalcula occafioned that of the plant: They began to fall from the branches as. fruit falls from the tree; and as they cradually feparated, the motive faculty was deftroyed. Spon- taneous extenfion and contraction were no longer feen, the vibration of the fibrilli at the mouth of ihe bell, nor the confequent vortex. Every fign ” of animation was gone; each animalcule became mifhapen, and was deftroyed. ‘The tree lived while it had animalcula ; after that it neither liv- ed nor vegetated; there was not the leaft indica-- tion of {pontaneous motion. Such was the fate of half the fpot which I had taken from, the - marfh lentil root and put in a watch,-glafs. I could now fee the generation of thefe animal fhrubs. Although the animalcula often died where they were produced and vegetated, that is, fat, / nition is, Vorticella compofita inverfe conica pedunculo & ramofo. The other is defined; Vorticella fimplex cam- panulata pedunculo retortili. Itis not in my power to decide whether they are really different or not. The de- | fcription of all thefe complicated animals will be. much better underftood by confulting the figures in Muller’ — work, P! ate 44. 45 2oret: I. ANrMaiLcuLA or INFUSIONS. 14G at the extremities of the bra nches, it was not un- common to obferve fome {wimming in the water, but always adhering to the limb or uae fince we thustetmit. If the branch accidentally touch. a lentil root, it immediately faftens, and gives ex- iftence to a tree bearing as many bell animalcula as there are branches to fupport them. The ani- mal attached to the root foon divides in two, then into four, eiglit, fixteen, thirty-two: While thefe divifions cr propagations are going on, the origin and multiplication of branches and twigs, bearing animalcula at the extremities, alfo ad- vance; and all the branches and twigs are im- mediately or mediately connected with the ftem fixed to the lentil root, already much thicker and longer; which ftem, properly fpeaking, is ' precifely the trunk of the microfcopic tree. Here I fhall remark, in pafling, that the animals, be- fides fixing and propagating on the marfh lentil, difo breed on other fubftances, as fragments of wood, ftraws, leaves of grafs, and even on the fides of the vellcls, provided they always remain in water. This fpecies, whofe mode of reproduCtion” Leeuwenhoeck could never divine, and was un- known to Baker, is a polypus much analogous to M. Trembley’s polype a maffé. ‘The refemblance is evident from that erninent naturalifl’s defcrip- tion of the {pecies which M. Bonnet calls polypes a kK 3 Pie e Py 50 ANIMALCULA OF INFUSIONS. Ty pennaches, (polipiafiocco). Befides, being clufter-- ed together like the fungi of rivulets, bellfhaped,. and producing a vortex, which. draws particles to: the mouth of the animalcule for food, and multi-~ plying by a longitudinal divifion, they are alfo at- tached to little twigs;. thefe to larger, and the: larger to. the common ftem ; and all the various: branches, as well as the ftem, animated by a moft remarkable motion of contraction and ex~ tenfion. Still they are different from M. Trem- bley’s,. for his produce a vortex, not by points, ef which they are deftitute, but by moving the lips of the bell; and, before divifion, by lofing the bell fhape and afluming that of a roundifh: corpuiculum: norvare they endowed with that. contraction and coniequent elongation :. they di- vide. into unequal parts, and the vortex ceafes. during divifion :. finally, the contraétion and ex~ tenfion of the branches is not natural and perio- dical, as in our-animalcula, but the effect of con-- # ftraint or accident, when the water is moved. All the longitudinal divifions yet fpoken of. have commenced at the anterior part of the ani- malcule, that is the part before when it advances,. and where the opening of a mouth may in many? be perceived. But the divifion of other animal cula begins at the part exactly oppofite, or be~ hind. My obfervations here were too late, and; / when, “ f. ANIMALCULA OF INFUSIONS. 157 when I had no draughtiman to defign them, therefore I muft content myfelf with a fimple defcription. One fpecies reprefents an infinitely minute hedgehog, or rather, fea hedgehog, being of a fpherical figure, and the whole furface co- vered with long*pointed prickles. The anterior _ part is diftinguifhed by advancing firft, and pro« " ducitig the ufual vortex, by vibrating the {pines : the reft are in conftant agitation when the animal advances. Another fpecies refembles the fegment of a {phere or a hemifphere, and is entirely cos vered with fpines: thofe on the convex part ferve for fins: others, appropriated to form the vortex, are fituated on the fection or plane of the ‘ hemifphere, which is always the aiiterior part of the animal. Allare difunited; and their fepara- tion feemed to {mooth the animal’s body, which. can move‘any number of {pines at a times © Aca cording to the number in motion, its activity, flownefs, and even the vortex 13 greater. Tl hele two fpecies which commonly inhabit the t fremella, and are of a eoloffal fize compared with many other infufion animalcula, divide longitudinally, but the divifion begins at .the pofterior part. A very faint cleft was feeh there as ufual; which extended more on the animal’s bedy, and at length divided it into two portions exactly ‘equal. They were not, as eafily might be imagined, two halves only, but, before the divifien finifhed, two . 4 complete * * 152 ANIMALCULA OF INFUSIONS. he complete animalcula equalling the fize: of the - whole. The vortex never difcontinues during divifion: minute {pines proceed from the cleft as it gradually advances, which, encreafing in length and thicknefs, m fome time are as large as the old.. ‘Two well formed. hedgehogs are produced’ by divificn of the firft fpecies; and two hemi-: fplreres armed with {pines by that of the fecond.. A confiderable period.is required for completing the feparation. Thefe being the moft fingular modes of longi-: tudinal divifion, I have thought it of confequence to enter on fome detail. Many fimilar propaga- tions lefs worthy of recital are omitted; and P prepare to’relate new methods of multiplication: by divifion of the B dy into pari A. fingularity is very frequently to be feen in an infufion of: ‘tremella.. ‘lwo minute pellets, attached together by many continued points, traverfe the fluid in: an irregular’ courfe, Pl. 1? fig’ 8. M.. We can-- not be miftaken if we fuppofe this an animal pre- paring to divide: infact it is fo; but one would be eeregioufly deceived if he formed an opinion ‘of what was to happen here. Judging by other animalcula, we fhould imagife it had hardly be-- gun, and that the cleft would encreafe till the animalcula remained attached. only by a point. It is otherwife; for in the twinkling of an eye, one pellet feparates from the other in {pite of the | apparent ees? Se be $ j \ Ks ANIMALCUEA OF INFUSIONS, 3254 © apparent ftrong adhefion. Each having attained the full fize, a faint contraction appears, which is the origin of two pellets fimilar to the firft, that in their turn feparate. ‘Thus do the animals propagate (1). Groupes of different round corpufcula are often feen in infufions of vegetable fubftances. Some- times the group confifts of four diftin@ cor- | pufeles ; fometimes of five or more: and the cor- pufcles are commonly different, according to the difference of the groupes, FigwS..N.. pls 1. Jt cannot be denied thefe groupes are real infufion animalcula : they poflefs every charaCeriftic ; but how are they reproduced? One corpufcle is de- tached after another from the clufter,. which is at laft divided intovas many portions as there were compofing animalcula.; and thefe begin to tra- verfe the infufion with much greater velocity than the refpective groupes to which they belong- ed. It might be objected, that 1 am {tating con- tradictions, and that the groupes are perhaps the cafual or intentional cluftering of animalcula, which feparate in a’given time, and thus occa- fion thefe apparent divifions. I had recourfe to a decifive experiment, ifolating fome animal- cula in a watch-glafs the moment they feparated from the clufter. When the folitary ones had acquired the fize of their original groupes, fur- rows (1) Monas uva. Muller, An, Inf—T. 64 ANIMALCULA OF INFUSIONS. © f, tows were perceptible on various parts of the ~ body, which by little and little was tranfmuted into a new clufter, perfectly fimilar to the old. The new group then decompofed into other corpufcles or animalcula, which in fize and num+ ber were equal to the former. I had the fame refults from experiments on three different clu ters: and we can make no conclufion, but that this is a new mode of a real and a€iual divifion. But the moft furprifing and fingular multipli- cation is that of certain animated globules, often rolling ‘along like pellets at the bottom of marfli~ lentil infufions, and vifible by the naked eye. They are compofed of external tumours, which are fo many animalcula, fituated above one an- other, and ready to efcape, PL. fig. 8. N M. Let the reader figure a body almoft fpherical, formed of concentric firata,; each of which is an ageregate of animalcula,—and he will havea fen- fible. idea of thefe globules. The animalcula compofing the exterior, or firft ftratum, feparate from the body, and fwim in the infufion: then is the fecond ftratum, compofed of fimilar ani- maleula, laid open. When all the firft have de- parted, thefe feparate from the body; and the third appears: ‘This alfo vanifhes by the depar- ture of the animalcula that formed it. There are even a fourth and a fifth ftratum, and others within to the laft in the centre; fo that the whole \ globe, " bs ' ANIMALCULA OF INEWSIONS, Thy | globe, from the circumference to the entre, is decompofed into a fwarm of animalcula. The compofing globe, I have obferved, has no: mos tion but rolling in the fluid ; however, the: ani- ~ malcula, when detached, fwim with the utmoft rapidity. ‘Their exceflive abundance renders it impoflible to number them; but, without exag+ geration, each globe confifis of a hundred (1). It might be fufpected that thefe globules are compofed of many animalcula, at firft feparate,, but afterwards collected together. I have had "evident proof of the reverfe. While the ftrata _ decompofed, I feized fome detached animalcula,, and immediately ifolated them. Hach (which did not equal one hundredth part of the globe in fize) was as large as the whole in a few days. Their motion relaxed in proportion as they grew 5 fo that when full grown, or complete globes, they had only a rolling progreffion after the man- ner of thefe animals. ‘The exterior ftratum. was. originally fmooth : it afterwards became unequal, and coyered with tumours. Thefe were as many diftin@ animalcula, which, in future, feparated from the globe to, traverfe the fluid. ‘The ani- malcula _ (1) Very much analogous to this, and the former, is the Gonium Peétorales’ It confifts of fixteen globular ani- malcula, invefted by a common membrane.——The mem- ‘brane burfts ; and each animalcule becomes the parent.of fixteen young.——T, an oa Y36 ANIMALCULA of INFUsIoNs: F malcula of the fecond ftratum did the fame, a$ alfo thofe of the remaining ftrata, until the globe was entirely decompofed. ‘This experiment was made on feven animalcula from different ftrata ; and all feven afforded me as many globes. Thefe are the different generations of animal- eula propagating by divifion, in the way hitherto explained ; and whiclrare in reality polypi that we will name infufion, or, more properly, microfco- pic, to ufe a general expreffion, as their kingdom is not bounded by the narrow confines of infu- fions. Y have, at various times, examined the, water of ditches, dunghills, ftanks, and pools ; fountain, fhow, and rain water; thermal and medicinal water, both of mountains and plains ; and I can affirm, that ] have found all more or lefs abounding with minute polypi of infinite va- riety. If the multitude is fuch, that a drop of water contains hundreds, may thoufands, as ex- periment proves, every one may conceive the number imexpreffibly immenfe, which fhould be contained in the recefles of all the waters fo amp~ ly diftributed over the furface of the globe (1). . : | Tt (1) The number will rife above all belief, if to the po- lypi of frefh water we add thofe of the fea; for, by Mul- ler’s obfervations, the fea abounds in animalcula peculiar to itfelf—-A. ; “ After the publication of thefe Traés, the author feems’ to a, I. ANIMALCULA OF INFUSIONS). 15% ¥ ‘It muft be remarked, that there are appointed: imes for thefe minute animals to originate, and’ e deftroyed, as with other creatures. that mulii- ply to excefs. Nature has. with the wifeft pro- vifion deftined, that-when one fpecies begins to: be exceflively numerous, it is reduced, either from the greater part of the individuals perifhing by difeafe, or a violent death by the voracity of other animalcula: tor it is a perpetual and’ in- violable law with numberlefs animals, that one lwes.on another, and mutual deftruction pre- ferves each fpecies. ‘The famevlaw is maintained - in the originating and deftruction of ‘our animai- cula. An infufion {warming to day will, in a few oe days, % to have extended his refearches to marine Animalcula’ Infuforia. ‘'The falt water, in which vegetable fubftances ‘ macerate and diffolve, contains numerous microfcopic be- ‘ings. ‘Thofe places in particular, where it is ftagnant and * fo fhallow that fubaquatic plants die and are decompofed, ‘fwarm with thefe minute animals. The fame phenomenon ‘happens in fea water kept in veficls, with vegetable fub- ‘ ftances diffolving. But what are the laws of nature regu- ‘ Jating marine infufion animalcula? Are they the fame ‘ with thofe to which the animalcula of frefh water are fub- ‘jet? Some of thefe propagate by the natural divifion of ‘ the body ; others are viviparous, and fome are oviparous. ¢ —Marine animalcula propagate exactly in this manner.? Lettera Relativa a Diverfe Produzione Marine.—T. oy 458 .ANIMAEGULA OF INFUSIONS. : aaa days, have almoft sone ; and, although thoufands perifh by a natural death, immenfe numbers are! a prey to the larger animalcula. Sig. Abate Corti has before me obferved fome kinds carry on the’ moit deftructive war. The ingenious method which, a cetaceous fifh, called by the northern nations the great whale, ufes to take herrings is well known: Having driven fhoals of them into a bay or ftrait, a blow is given with its tail, fo as to occafion a whirlpool of vaft ‘extent and great rapidity, which draws in the herrings; ‘the fea monfter then prefenting its enormous mouth and tremendous jaws, the herrings are precipitated down.the throat, and its ftomach is foon filled. The carnivorous infufion animalcula, of which we treat, ‘alfo create a’vortex in the fluid by their vibrating-fibrilli; but they are under no neceflity of confining the animalcula inynarrow limits. If abounding in infufions, they have only to keep their mouths open ready toiingulph them: if rare, they:trace themvout, and ‘fwallow them up. So voracious are they’ as' to’feed till they appear much larger: then-thé "purfuit is no longer in- terefting : the anittalebécome indolent and flug- gith. Onval cotitrary, if reduced to abftinence fome time i UHHHed water, they are full of {pi- rit, and eagerly devour the minute animalcula fupplied. The tranfparency of their bodies al- lows b ibe ANIMALCULA OF INFUSIONS, 159 lows us to fee the animalcula, whofe motion con». tinues after being fwallowed (1). — “All the divifions may be feen in every feafon, even the coldeft and moft rigorous. Heat as. much promotes it as it is retarded by cold: and ‘ we may affert, that the time required for divifion is nearly in proportion to the heat of the atmo- fphere, In the iniddle of winter, it takes many hours: in {pring and autumn, it is fooner per: formed : and finifhes very foon in fummer, efpe- cially if great heats prevail. Sometimes leis than a quarter of an hour is then fufficient from the beginning to entire completion. ‘This is one chief reafon why fummer infufions are much fooner peopled than winter ones. " Whoever wifhes to employ: himielf with thefe curious obferyations, and the fingular modes of . ‘ multipli. ‘* (1) It is fingular, that Muller fhould deny that animalcu-_ - la prey on each other. Some {pecies he fays prefer being a- mong the particles of duft, animal and vegetable fragments, and feem to take pleafure in gnawing them; but he can ea- fily fuppofe, that water alone may be their*only nutri- ment, as he has feen the life of large animals, fuch as Hy- drachnae or Entomoltraca, fupported by water, Praefat. p. 12,13. However, he gives the figure of an animalcule - containing one devoured, p. 165.—T. . oe %60 ANIMALCULA OF INFUSIONS.” YY #rultiplication by divifion, and is unwilling to fix the eye too long on the microfcope, fhould pre- - fer fummer, if he does not chufe to have recourfe to a ftove, which my experiments prove operates equally well. ' CHAP. VIII. SEVERAL INFUSION ANIMALCULA ARE OVIPAROUS: SOME VIVIPAROUS: AND ALL HERMAPHRODITES IN THE STRICTEST SENSE. i my microfcopic refearches, 1 have obferved, that many fpecies of animalcula become extremely numerous in'a very fhort time, without evincing any figns of divifion. How, then, do they propa- gate? Shall we fay it is by inftantaneous divi- fion, and on that account not eafily perceptible : or that it is effected in any other manner? Ex- periment, the only method of diflipating doubt, has fhown us that this propagation was not the confequence of divifion, but from eggs, and fome- times minute foetufes; for I have actually found many kinds of animalcula oviparous and fome vi- viparous. Such an affertion is nothing unleis fupported by convincing and decifive evidence. ra The ye ANIMALCULA OF INFUSIONS. 161 The reader ought fo much the more to defire -conviction, as this is pofitively denied by Meffrs Needham and De Buffon, who exclude: univocal generation from infufions entirely. ‘Thus it be- comes neceflary to defcend to circumftantiate de- tails; at the fame time preferving due attention -to brevity. ‘One oviparous kind of the largeft fize among -animalcula is found in rice infufions. It much tefembles the. figure of a kidney bean, except that -one extremity is curved into a fharp beak, Plate 1. fig. 9. O.(1). Having feen the wonderful mul- tiplication of this fpecies, without being able to ‘difcover whence it arofe, I thought of recurring ‘to ifolation, which on many occafions had been fo ufeful an expedient. One was, therefore, put in the ufual glaffes with a little water, which, for ‘fecurity of containing no animalcula, had been a long time:boiled. In feven hours, the animalcule was not alone, it-had a companion. The new gueft was fo like the old.one, it was impoffible to diftinguifh them. I had no reafon to fuppofe that it came from without, or was produced by ‘the infufion. When the animailcule was ifolated, -equal portions of the fame boiled infufions were Vou. I. L ‘put (1) The Kolpoda cucullus of Muller: It*has‘from to 24 pellucid globules within, which he thinks are the rofispring ; in the young animals, none are to be feen, Anim. Infuf. 103, 104.—D. - ‘ 462 ANIMALCULA OF INFU foah ¢ Pihie ere was one. Butnone either of one ahteh Ps 4 Ag eaue re put into feven ye Brent, amie” for the | I comparing what ‘mig cht happen in gle _ there were original} y no animalcula, al another ever appeared in the feven glafl es i thought “es right In concluding, that ynd. animalcule derived its origin: fe rt: This might Rye in various ways 5 ther the firft id produced the fecond | laid an egg from which it came, or by di in two. More recat examination of the § was required for difcovering the truth. an hour, I found fomeiiane new: t two nl pellets at the bottcm of P the alals, PQT fig. 9. One was ovals it moved from. ' time; and in moying changed its place. nate motion and reft cobtinued an hour third : then it was more frequent and a cal, the pellet beginning to. fwim flowly t the fluid. After the lapfe of fome time, its : was as coniiderable as ge of the two anit ‘This, its equality in fize to them, being p at the extremity, and apparently compofed the fame vafcular fubftance, evinced it to 1] animalcule of the fame nature, ‘expanding grees, and now become moft active. ~ Ai elliptical pellet prefented thefe phenomer round one O exhibited others. Withi cluded a lefler fohere difficultto be obferve oa gg ANIMALCULA @F INTUSIONS. 163 which J perhaps fhould not. have noticed had it not been fora gentle revolving motion uponitfelf, while the including {phere was tranquil. After various revolutions, the fhell burft, and the Jefler fphere -efcaped: the envelope was reduced to a wrink- led irregular fubftance. The {pherule extended, -and grew fmall at one end to form the curved beak; and.it began-to fwim: .thus affuming all the characteriftics of an animal which the other had. The origin of thefe animalcula is, there- _fore, from an egg, reprefented by the fhell or in- _volucrum. But the conje€ture required further and more decifive proofs to become an eftablifhed fa& ; and Such | foon obtained. The glafs being left in that _itate on the evening of 15 June, next morning there were more than forty-five animalcula, all _exadtly refembling the firft which was ifolated. At the bottom a.number of pellets appeared, part round, part elliptical. With my eye intent on the round, I perceived they did not become elongated, as the pellet mentioned above: one after another burft, and as many inactive mifhapen animalcula came out, afterwards growing into complete fi- _gures full of action. When the fmaller became larger, they did the fame. Thefe fubftances were — undoubtedly eggs ; fill it was to be elucidated . whether they had proceeded from the animalcule, _which was more than probable. For abfolute | EN) conviction, 164 ANIMALCULA OF INFUSIONS. ‘Ie conviction, it was neceflary to fee them proceed from its body, which appeared difficult, not fo much from the rapidity of its courfe, as becaufe it left the field of the microfcope every moment, from too great abundance of fluid. The fitteft method was confining fome ina very fmall quan- tity of water, that they might be conftantly in view. I did fo; and the fuccefs was feoner than I could have expected ; fince, in f{carcely a quar- ter of an hour after confinement, one was deliver- ed before me of a round corpufcle fimilar to the former: and it having opened, gave birth to cne of the ufual animalcula, firft round, then oval, then diminifhing into a curved beak, and com- mencing motion in the glafs, as had happened to its other companions. More eggs were produc- ed: I counted eleven that had proceeded from the pofterior part of the ifolated animalcule, pro- ducing an equal number of young. I might have counted more had not fuch very minute obfer- vations exhaufted my patience. From the whole, it is clear that thefe animalcula are oviparous, and their mode of propagation by eggs. This particular detail will render fuperfluous what I fhould have had to fay on many other fpecies alfo oviparous. I can only. affure the reader, that by fcrupuloufly practifing fuch a plan, each fpecies has laid eggs which produced ani- ~ ¥ Be _ = ce malcula fimilar to the mother. »Some of thefe 4 ‘ animalcula, — ried ANIMALCULA OF INFUSIONS: i6$ animalcula, round or cylindrical, originate in in- _ fufioris of radifh and camomile feeds, beans, and buck-wheat. Let us next treat of viviparous animalcula, of which I have found two fpecies, both carnivo- rous. We diftinctly fee the animalcula abforbed by a great vortex, pafling down the cefophagus into a little bag, and thence into a larger, appa~ ‘rently ferving for a ftomach. Each animalcule has a long tail forked at the extremity, by which it can attach itfelf to the adjacent fubftances. ‘Two oval bodies project from each fide of the tail, and above them two fimaller, refembling narrow le-ves, Pl. i. fig. 10. R. It is eafy to fuppofe thefe four bodies integral parts of the animalcule ; and the two leaves are actually fo; but the other two are real animalcula. We not only perceive them move, but, examined by a powerful magnifier, they are evidently two living animals, refembling the large one, to which they are attached, but confined and contracted within themfelves. If kept in view, they gradually expand, are eman- cipated from the mother, and begin to {wim. The opacity of this kind prevented me from fee- ing the foetus before it iffued from the body. After an animalcule has attained maturity, two young ones are feen where the tail originates. I have never difcovered more or lefs. than two in all the animalcula I have examined. In other L 3 animaicula ad 1662 ANIMALCULA OF INFUSIONS: EP animalcula three are to be feen, but them h- judged of a different fpecies, becaufe the leaves. were wanting, and the interior feemed fomewhat. different, Fig. 10.8: Thefe two kinds of ani- malcula are commonly among the tremella of: ditches. ‘ Is copulation required for the propagation »of | their race by oviparous and viviparous animal-- cula? If-I faid that I had once beheld a real. copulation, ever fince I ftudied infufions, it would. be advancing what is dire€tly oppofite to truth.. But, adhering to the principles of {trict logic,, from: which the naturalift fhould never deviate, - x10 legitimate confequence can thence be deduced that they do not copulate. Like that of other: animals, copulation might be inftantaneous,. and: therefore efcape obfervation. It was poflible. that, the eggs of oviparous animalcula might be fecun-- dated after. exclufion from the body of. the mo-; ther, the fame as-thofe of frogs and toads: there-- — fore I: had to attain the truth, by obviating every, pofhbility.: of the contrary, which was accom-: plifhed in the following manner. Having put, the egg of an animalcule in a watch-glafs, I cone’ cluded, if the animalcule from this ifolated egg; produced a fertile egs, there would be no need for copulation: if a fterile one,, that more, than- one individual was requifite for propagating the {pecies, that is, copulation was effential. But the truth. is, as) many animalcula were produced as * egges a ANIMALCULA OF INFUSIONS. #67 eggs laid by. the fclitary animalcule, which fuc- cori’ with all the {pecies 1 examined (1). » A fimilar method was purfued with vivipar- ous animalcula, by taking feveral young, one by one, from the parent belie being fully. pi elop- ed, and ifolating them to prevent all fufpicicn of mutual intercourfe. Each ifolated animalcule, in. due time, became parent of other two, that 13, of two, {peaking of the firft {pecies, and three, {peaking of the fecond. And thefe young after- wards had defcendants (2). Thefe two genera of oviparous and viviparous animalcula are, therefore, hermaphrodites in the L..4 . firicteft (1) Some authors indeed deny the copulation of ani- malcula. Roffredi fays he has been long acquainted with mMicrofeopic animaleula, and known the frivolity of their pretended copulations: immediately afterwards, however, he defcribes that of the eels of blighted corn. Several in- ftances are related by Muller. The copulation of the Pa- ramecium Aurelia has continued two hours, Anim. Lnfus. p: 58. Lhe Tiichoda Aurantia, Prifma, Lynceus, co- pulate ; as do the Vorticella Hamata, and, Crateriformis, p- 185. 188. 226. 278. 279:.280. Hie has feen. what he calls both a-tranfverfe and longitudinal copulation of the Trichoda, Ignita, and Charon, p: 186. 230.—T. {2) The Vorticella Nafuta propagates both by produc- ing living fetufes, and by ihe divifion of its own body into four parts, Muller, p. 269. In this ic fomewhat refembles other animals that produce both eggs and young. —-T. 168 ANIMALCULA OF INFUSIONS. I. ftricteft fenfe. When we find infufion animalcula propagating by divifion to be fuch, fince ifola- tion does not prejudice their multiplication, it may readily be feen how far abfolute hermaphro-. difm extends:in the animated world, though for-- merly limited to few fpecies. This difcovery tends greatly to elucidate a dif-. ficult queftion concerning the original inhabitants+ of infufions. Some time after an infufion is made, . it will be fwarming with animalcula, though the. utmoft. precaution is ufed againft any one being- concealed; and for greater fecurity it is boiled: feveral hours. I afk, How do the original foun- ders of the future moft numerous inhabitants. come there? I can conceive only. two ways3.. they muift either have pre-exifted. in the infufion mixed with it, or they muft have come there by. means of germs. The firft opinion cannot be adopted; for had they pre-exifted in the infufion,. we are obliged to admit that they would never™ die when out of a fluid, or that they revive when: - reftored: to one, as the wheel animal and fome other animals do. But experiments without: number have demontftrated to me, that the-in-. habitants of infufions die irrecoverably on evapora-- tion of the liquids (1). Thus there is a-neceflity: for: {1) Muller, befides quoting Wrifberg’s experiments, . and mine, fays he has obferved the fame. Decantatus in-. fuforiorums = 6 a ae he ANIMALCULA OF INFUSIONS. 16g for recurring to the fecond mode, namely, to fome germ or ovulum paffing from the air into the ine fufion, and becoming the origin and fource of fo numerous a race of creatures. Such an inference acquires. fuforiorum vere demortuorum, Vibrionem anguillulam f excipias in vitam reditus mihi fefe nullo experimento pro- bavit, nec acutiffimis obfervatoribus, Spallanzani et Wrif- berg fucceffit, neque quomodo eadem revivifeant perfpicio eum corpora plerorumque poft exhalatam aquam rumpi, et in moleculas efflari manifefte video.—A. Here Muller evidently fpeaks of eomplete death. In the fecond edition of the work alluded to, the Animalcula Eufuforia, fome additional remarks are fubjoined to thefe, which the author has not proceeded to quote.——* But a drop of water being fupplied, before complete. rupture of the. parts, motion and life will return; though, from the violence the animal has fuffered, a degree of languor will for fome.time, or always, remain. If the animalcule is defended from tie injuries of the air, by means of any particles of duft or fand cafually in the infufion, and the- humidity not entirely exhaufted, it will recover. Some are deftroyed and totally diffolved by fimple conta of the air. Ihave feen fome decompofed on approaching the edge of a drop; and even others, amidft the rapidity of their courfe, I have feen diffolve in a moment.” Perhaps all animals are fubje@ to inftantaneous death: It is frequently found in infects. But the apparent death ef animalcula will often proceed from inability to move . s the members, except in water.—T, ¥7o ANIMALCULA OF INFUSIONS» » If acquires more force and perfuafion when fupport> ed by facts. I allowed the fluid about animal- cular eves to fail, fo that they remained quite dry ten days ; then they were reftored to their. native liquid :—befides being revived, they were foon hatched. From this there is no difficulty in conceiving why animalcula originate in infufions: where there are originally none; efpecially by reflecting on the immenfe abundance difleminated through the air and on terreftrial fubftanees ; and confidering the innumerable animalcula inhabit~ ing the waters of the globe. ; Every fluid is not equally favourable to the ex- panfion of animalcular eggs. Pure water alone is unfitifor it: hence it is no longer a myftery, why in it, and much more in diftilled water, we . hardly ever fee animalcula- On the other hand, they always originate in the water where vegeta- ble feeds are macerated. I have found: no fluids better adapted to the production of eggs than _ thofe where infufed feeds began to corrupt. The appearance of animalcula fhews, that incipient putrefaction creates qualities in the decompofing materials fit for developement of the egg: for fuch is the tenor of nature, that eggs are nat excluded wherever they happen to be, or in every cafe, but only in fuitable fituations, and by means of certain determinate conditions. I have a ANIMALCULA OF INFUSIONS. epee _ [have particularly examined whether animal. cula were fpecifically different, according to the, difference of the feeds infufed and whether each. had its peculiar fpecies. Here I have found no. uniformity. Certain {pecies only have been. found in particular kinds of wegetables; but it often happens otherwife. Beth at different times. and different places is there a variety in the ani- malcula of the fame infufion: and it is not un-. common in two infufions of feeds, taken from. the fame plant, made at the fame time, and kept in the fame fituation ; a fact which well coincides, with the vaft variety of animalcular eggs diffemi- nated in the air, and falling every where without any law. If we can affirm that all the fpecies, multiply- ing without any apparent divifion, do fo by means of fome pre-organifed principle, as is moft credi- ble, it muft be allowed they form a moft intereft. ing part of our animalcula. The other clafs, propagating by divifion, and thence called mi- croicopic polypi, prefent fomething {till more interefting. What can we think of their origin, in infufions? Doubtlefs they alfo proceed from fome pre-organifed principle: but is that a feed, an egg, or other analogous corpufcle? If facts are demanded, I acknowledge we have none ; as. thefe polypi die when deprived of the fluid, nor do they revive when it is reftored, we cannot be, lieve they fall from the air. I have no fenfible evidence 192 ANIMALCULA OF INFUSIONS. i evidence of their originating from a pre-organifed principle, fince it has never been difcovered by me; but, adhering to eftablifhed faéts, this « opi- lion is to be embraced: for, if the polypi, fir feen in infufions, are not produced by plaftic or vegetative powers, which fo many facts have proved chimerical, and cannot be the fame that fall from the air into the infufion, it is moft ra- tional to infer, that they proceed from fome germ, or pre-organifed principle, whatever it may be called. It is of no importance whether the germ or feminal principle is invifible, or reproduc tion of the polypi effected by means of divifion ; becaufe, with refpedt to the firft, we know that we ought not always to conclude on the non-ex- iftence of a thing which we do not perceive ; and - in the cafe before us, the germs may be either too tranfparent or too minute to fall under our fenfes ; and with refpect to the fecond, this is not the on- ly polypus which multiplies by germs or eggs, as fome others do the fame. I have fuppofed that the germs whence animal- cula originate come from the air; and this ap- pears moft reafonable from the fupport of un- doubted facts, which I fhall briefly enumerate (1). Sixteen (1) Maller alfo thinks it probable that animalcula and their eggs come from the air. Praefat. p. 22, 297, 298; oT {, ANIMALCULA OF INFUSIONS. 173 Sixteen large equal fized glafs veffels were feledt- ed and divided into four claffes.. Four were her- metically fealed ; four {topped with wooden ftop- ‘pers, well fitted ; four with cotcon ; and tthe re- maining four left open. By this means the exter- nal air had no communication with fome; very little with others, with the third clafs more, and as free as poflible with the reft. Every four con- tained infufions of hemp-feed, rice, lentils, and ‘peafe ; and were boiled a full hour in the vafes before being clofed up. I began the experiments 11,May, and vifited the vafes 5 June. In each were two {pecies of animalcula, large and fall; but the four open infufions were fo full and crowded, that they feemed to teem with life; with the cotton ftoppers, they were about a third f{carcer ; and the animalcula {till fewer in the vel- fels with wooden ftoppers ; in thofe hermetically fealed were fewelt of all. The effence of the experiment was the fame on taking maize, wheat, and barley for infufion. Inftead of ufing ftoppers, I covered fome of the infufions with nut or olive oil ; and this new obftae ‘cle further diminifhed the number of animalcula, The immediate confequence refulting from thefe facts is, that animalcula are more numere ous in proportion to the communication of the infufions with the external air. From what we fee, their origin is cither from germs brought by the «274 » &NIMALCULA OF INFUSIONS, 2 ft % the external air to the veflels, or, being mixed with the infufions, it concurs to aid the expan- Mion of them. That fuch germs may be partly mixed with infufions, and the air promote their evolution, I have no difficulty in believing. But the faéts hitherto related, evidently demon- _ftrate that the air ferves as a vehicle to them ; and _as it is impoflible in this cafe to recur to thofe of the infufion, which fhould have been deftroyed by boiling for an hour, we are under the neceflity of referring to thofe of the air. ‘This fluid entering more freely and copioufly, fhould convey a much greater number of germs into the open veflels, and of confequence the population of the infu- fions fhould be greater. The reverfe will hap- pen, where little air enters and penetrates with -more difficulty, as when the veflels are ftopped .with wood. ‘The volume of air included in the veffels hermetically fealed, will produce the ani- malcula appearing there, but few in comparifon to thofe m open veflels, on account of the rare- mefs of the producing germs, which are propor- tioned to the fmall quantity of air that is never renewed. CHAP. ry * i “ %, ANIMALCULA OF INFUSIONS. v7 ef CHAP. IX% ANIMALCULA POSSESS THE REAL AND CHARACTER. ISTIC MARKS OF ANIMALITY. "Tek eaiftence 6f an immaterial and@entenc . principle in anima's, refts on the analogy between. their organization and operations compared with the organization and operations of man. Many who hhavehad recourfe to this kind of analogy, -thouch profound metaphyficians, have not been naturalifts enough to examine it as it ought to be. Surely they have not taken the animal pro- greffion in its full extent, nor defcended to a juft and rigorous analyfis, which would have demon- ftrated the ineflicacy of analogical reafoning in “many links of the animal chain. Without any intention of combating their laudable ideas, let us take a view of them ; and firft of the animal organization. It cannot be denied, that the me- chanical ftructure of numberlefs animals corref- ponds entirely or in the greater part with that of man. Not to name the oran-outang fo fimilar “to us, as differing only in the privation of reafon, - quadrupeds and birds in this refpe&t could not ap- proach nearer to the human fpecies. ‘The fame organs for digeftion, refpiration, circulation, fe- cretion 3 76 § ANIMALCULA OF INFUSIONS. BY cretion; the fame ramifications of nerves from the fpinal marrow, the origin of this from the brain, and the fimilarity of its confiftence; the fame meandring of veins and arteries, producing innumerable rivers and rivulets through the whole body, conveying life and nutriment every where. No difference is perceptible in the a€tion of the mufcles, ligaments, teguments, cartilages, or ten- dons: the fame variety in the nature, the mo- tions, and offices of the bones. Some long, fome bent, fome curved into an arch. The hardnefs vies with that of ftone in fome: in others, the pliancy is equal to cartilages. ‘Some are hollow and filled with marrow; others folid and mafiy throughout. Certain bones confift of a fingle piece, while various parts connected together form others. Laftly, all thefe animals have the fame number of fenfes, and the organs of them fituated in the fame parts of the body, and con- firu€ted as ours. But it has pleafed nature to diverfify the figure of thefe animated ma- chines: fometimes arming them with tufks, horns, nails, or claws: fometimes clothing them with fcales, adorning them with feathers, or cover- ing them with a hard hide; diminithing the ante- rior part of fome ito a pointed beak, a flender fnout, or a long and monftrous trunk ; or en- larging it to form a hideous head, frightful to be- hold, or exciting pleafure by its refemblance te our 4. ANIMALCULA OF INFUSIONS. 177 “our own. This ingenious creatrix has formed the body of fome fo as to convey an idea of Jightnefs and grace ; while others difplay a floth- ful inadtivity : one is contracted within itfelf, and apparently only of a fingle piece; another ex- tended beyond all bounds ; and a third moft ex- actly proportioned. In a word, there are as many varieties among birds and quadrupeds as their forms are different from that of man; yet in every one is there the narroweft refemblance in ‘the effential part of organization. Analogical reafoning applied to thefe two races of animals cannot ‘be {tronger or more convin- cing ; but how is it ‘weakened by defcending the animal f{cale to fifhes, reptiles, infects, and at laft is totally loft. Let us attend a moment to the ftruCture of infects. Not only do the bones, blood, heart, and other vifcera difappear, but we cannot difcover either veins or arteries. A lon- gitudinal veflel from one extremity to the other is feen, in which flows a liquid generally tranfpa- rent. Although the nervous fyftem is maintain- ed entire, there is no brain, at leaft nothing pro- perly fo: and their refpiratory organs much more refemble thofe of plants than thofe of the larger animals. Defcending the animal {cale {till lower, every femblance of organs is loft, and the whole body of the animal is reduced to the moft fimple ftru€ture imaginable. Many polypi are Vou. L M buf 178 ANIMALCULA OF INFUSIONS. 1, but an elongated faeculus covered with tuber- cles: Many aquatic animals are fimply of a mem- -branaceous or vafcular texture. Many. marine zoophytes are only a kind of jelly. ‘The organi- zation of thefe animals has not the fmalleft rela- tion to that of man; plants themfelves may be faid to refemble him more, becaufe we find fap -veffels, utricles, and tracheae in them (1). The (1) Every fmall animal was formerly called an infed, and is fo ftill, by incorre@t writers. The fub-divifions of animated nature muft become more numerous, in propor- tion as fcience advances, and peculiar diftinétive properties are difcovered. A great family has been feparated from proper Entomology, and called cruffacea: but another, “much more immenfe, has been removed farther under the name Vermes; and additional changes are made by every new writer. But it will be long before they are univer- fally obferved, particularly in imperfect infects and worms. It was generally believed, that none of the animals de- nominated infects had any brain, and very few ventured to difpute the fact ; and after they did fo, the reverfe was pertinacioufly maintained. Halfer lays it down asa general rule, that all animals, having a head and eyes, muft alfo have a brain and fpinal marrow: he thinks, neither eyes without a brain, nor a brain without eyes, exift in any animal; likewife, that all thofe with a brain and fpinal marrow muft alfo have nerves, Phyfiologia, Tom. 4. p. 2. 4 ss. Fabricius fays, infects have only the rudiments of a brain, i. ANIMALCULA OF INFUSIONS. 179 The degradation in the organic ftructure of ani- mals is alfo vifible in their operations. Thefe, in ‘many fpecies, nearly approach to thofe of man. Such are the operations of quadrupeds in gene- ral; but more efpecially of the elephant, ape, and beaver. Thofe of birds, likewife, bear much analogy to ours: their ingenuity in con{tructing nefts ; the diverfity of note to exprefs the vari- ous affections of hatred, fear, pleafure and pain; the provident fagacity of many, in changing their climate according to the charige of feafons ; the _ facility of inftructing birds of prey for the chace : M 2 all brain, Entomologia Syftematica, Joni. 1. In one treatife, . the great comparative anatomilt Cuvier affirms, they have no brain properly fo called, but only a fpinal marrow, fwelling into knots and tubercles at intervals, from which the nerves proceed, Fubleau de L’hificire Naturelle des Ani- maux. ‘lowever, in his late work on Comparative Ana- tomy, he defcribes the brain of many infeéts divided inte two lobes, and fending forth nerves. The nervous fyftem of the various genera of worms is much more obfcure. _According to Virey, Cuvier, and others, they have no brain, but ganglia on a nervous cord. The latter re- marks, ‘ Ganglia nearly equal being uniformly diitributed * onacord, extending through the whole leagth of the * body, feems defigned to furnifh each fegment with a * brain peculiar to itfelf.? Neither brain nor nerves have yet been difcovered in the actiniz, medufe, polypi, and Many more.—T. 180 ANIMALCULA OF INFUSIONS. 1, all are qualities proving what I advance, But this analogy exifts no more, when we come to fithes, reptiles, and infects. It is true, that a- mong the laft are many diftinguifhed by their operations : whether confidered by their anxiety for felf-prefervation, purfuing what is ufeful, and avoiding what is noxious; whether we confider their mutual anxiety for propagating the fpecies, or fingular folicitude for their young, placing them in fuitable fituations, and proyiding them with food until they need maternal affiftance no longer. We all know-the ingenuity of bees, the fagacity of the leaf-moth (tignuola delle foglie), ihe induftry of the ant-lion and fpider, the fero- city of the hornet, or the ingenious cruelty of ichneumons. But the operations of numberlefs other animals are reduced fimply to feizing and {wallowing their prey, as the arm-polypus; or to open and fhut their fhells, as many teftacea ; or imbibing nutriment by an immenfe number of mouths on the furface of the body, as many ma- rine animal plants. | By this hafty glance at the animal fcale, we arrive in the degradation at a race of beings, which, to judge of their ftru€ture and operations compared with thofe of man, we fhould be more inclined to deprive of a fentient mind than to be- {tow one upon them. Behold how much analo- gical reafoning is enfeebled in the intermediate claffes, f. ANIMALCULA OF INFUSIONS. 18 clafles, and totally loft in the loweft, though ap; pearing fo evident and conclufive in the higher degrees! Can we thence aflert that animals oc- cupying the loweft rank bear the name of ani- mals improperly, from being apparently deprived of an immaterial and fentient principle? This has already been fufpected by Bonnet: he who, both as a profound metaphyfician and a moft able naturalift, has confidered the gradual pro- preflion of beings fo well. After fuppofing, in the. Corps Organifes and the Contemplation, that the polypus is a real animal, and, on this fuppofition; explaining the moft embarrafling phenomena in his Palingenefie, he does not hefitate to hazard a mechanical explanation, by confidering the poly- pus as an animal fimply vital, or endowed with irritability alone ; and fufpects there may be other animals fimilar from the fimplicity of their {truc- ture or operations. Needham goes farther: All animals that repair their parts, loft either by an- putation or by natural divifion, are, according to him, animals /mply vital, in which he places the immenfe kingdom of infufion animalcula, fince, by M. de Sauffure’s difcovery, they pro- pagate by divifion(1). But he is lefs inclined to | M 3 exclude (1) Thereis fach an immenfe varisty of animalcula, that it is very difficult to fay what clafs they belong to. Some late writers clafs them among worms, and fome a- mong 182 ANIMALCULA OF INFUSIONS. bb exclude them from the rank of animals from too great fimplicity in firu€ture or operations, than his inability to conceive how an organifed being reproducing by divifion can have a foul. That beings fimply animated, or animals whofe life confifts only in irritability of the parts, are poflible, I can eafily believe; efpecially when {peaking of thofe whofe actions are few and little varied, and that by this hypothefis the gradations of organifed beings is better united by connec- ting the animal and vegetable kingdoms by means of fuch fimply vital or irritable beings, inferior to an animal, and fuperior toa plant. That it is poflible infufion animalcula may be of the num- ber, I offer nothing again{ft : nor will any thing in the leaft difadvantageous to it be feen im what has yet been faid in this Tract. Earneft, how- ever, to reduce poflibilities to faéts, Iam much more inclined to judge them: real and a@ual ani- mals than beings fimply vital or irritable. There is - foundation for my opinion, becaufe an afflemblage of qualities is recognifed in them fufficient to con- ftitute the qualities of abfolute animality.. I have had occafion to remark fome of thefe qualities in. my Differtation, fuch as the exertions of animal- cula. mong zoophytes. If our microfcopes could difcover thzir internal ftructure, it is moft probable that many would be removed far from both—-T. 7 ra ANIMALCULA OF INFUSIONS> 183 cula to avoid each other and the obftacles to their courfe ; fuddenly changing their direction, taking an oppofite one; and pafling inftantane- oufly from reft to motion, without any external impulfe ; eagerly darting to particles of the in- fufed fubftances ; inceffantly revolving on them- felves, without a change of place, their courfe againft the current, and crowding into fhallow — parts of the fluid (1). Neither have other cha- racteriftics, (1) M. Guettard, in a work which, from the prodigious multiplicity and variety of matter, might be called a trea- tife de omnibus rebus et quibufdam aliis, is convinced that in- fufion animalcula are only the farinaceous veficles of feeds put in motion by external caufes: and with this convic- tion does he judge it proper to difcufs the qualities I men- tion; all which he efteems infufficient to prove the ani- mation of animalcula. To adopt his mode of reafoning, it would be a matter of very great doubt whether hories or elephants were real animals, though poflefling the fame qualities. But the moft wonderful circumftance is, that the author is perfectly innocent ef all thefe matters; and evidently fhows that he has never feen a fingle infufion animalcule in his.life. It would be lofing time to demon- {trate the frivolity of his arguments, fit for the ignorant only. The reader may confult the author himfelf; and that he may not think me exaggerating, he is referred to Muller, who, without the leaft connection with me, cither by friendfhip or literary intercourfe, undertakes my defence; Ma or 184 ANIMALCULA OF INFUSIONS. i racteriftics, forcibly corroborating their animality, failed.to occur in the compofition of this work ; partly deduced from. various accidents to which they are fubjeét, like other animals, when put in fimilar fituations. For the reader’s convenience, I fhall bring my different experiments briefly into view: from the recapitulation, he will be more enabled to under- ftand the ufe of comparifon, which, as he already knows, conftitutes no {mall portion of the work. Too great heat deftroys animal life: 111° is fatal to the tadpoles of frogs, and:to frogs them- felves, or rather the defence of truth. Impreffo huc ufque libello in manus venit folium 30 novel. Lett. Gottingenf. 17725 ubi clariff Guettard animalcula infuforia meras vefciculas farinaceas arguere indicatur. Accerfito libro (memoires fur differentes parties: des Sciences et Arts, tom. 2. Paris . 1770) avidiffimeque, quae de his agunt perlettis, et quafe devoratis, vultu tamen continuo fubridente non potui, nom admirari do¢tiffimi viri temeritatem, argumentis, quae folo ingenio debentur (veftigium enim obfervationis ulliug infuforii ab ipfo -inftitutae nullum: extat) tentandi refuta- tionem: eorum, quae meris obfervationibus innitunturs Nec abfque apparenti fucceffu, licet enim meliora clariffy Spallanzani-argumente pro- animalitate infuforiorum pug: nantia in aream producat, cuilibet leGori, obfervationum aeque ignaro, ac ipfe, fucum facit, quem tamen unaquae- gue infuforiorum contemplatio difpellet. In re enim nas turali non ingenio, fed obfervatione vivitur. Hi ANIMALCULA OF INFUSIONS. 185° felves, the nymphs and larvae of mufkitoes,. and: to water newts: 108° kills filk-worms and the: larvae of the blue flefh fly: 106° kills leeches, rat-tailed worms, and. water fleas: and animal. cula die at about the fame degree of heat, that is 106°, 108°, 111°.. All animalcula are not alike affected by: cold.. Some die at freezing, or a degree not much; greater ; others furvive at 10°.. Thus is it with, infects. Winter deftroys moft of them, but many brave its rigour, and fome retain the ufe of theix members, as is feen in various {pecies of infufion, animalcula. During fummer, I have often fro-. zen water in a concave glafs where different little infects fwam. Freezing began at the circumfe- rence, and formed a wreath of ice: but the in- feéts never remained to be imprifoned in it ; they retreated to the interior where the water was yet. fluid, and, as freezing advanced, colleted in the centre of the glafs, where they perifhed on com- plete induration of the fluid. Infufion animalcula. exhibit precifely the fame phenomena. The odours and. liquors that are. a virulent poifon to infects, are the fame to animalcula.. Such is the odour of camphor, the fumes of tur- pentine, fulphur, and tobacco. Oleaginous, {pi- ritous, and. faline liquors are equally deftructive. The electric fpark is a real thunderbolt to both. Agents flowly deftructive of infufion animalcula are 186 ANIMALCULA OF INFUSIONS: fi are likewife fatal to infects, as the vacuum an air pump. The motions of animalcula concur in proving their animality. They are not the fame mall, but different, and produced by different means peculiar to each fpecies. Many move in infufions only by undulating the body, as eels do in fwim- ming. ‘That undulation is not fimilar in every one; for fome form ‘a few flight curvatures, o- thers deep and numerous. ‘The figure is formed in a moment by fome, by others flowly and gra- dually. The arms, points, and fibrils, proceed- ing from the extremity of the body, are inftru- ments for many animalcula to fwim: fome are long, fome fhort, fome ftrike the water often, others feldom, and the reft with various degrees of velocity. There are animalcula whofe motion is very languid, and there are fome that move moft rapidly. Some move at intervals ; the mo- tion of others is perpetual: they never feem to reft. I have feen one fpecies whofe pofterior fibres, difengaged and feparated far afunder, folding to- gether in an inftant, darted the animal to a confi- derable diftance, like an arrow from a bow. The courfe of feveral fpecies never deviates from a ftraight line ; others continually pitch up and down like a veffel at fea. Some whirl like tops or balls on themfelves, without moving from the {pot ; while others have a progreflion during this rotatory i; $ANIMALCULA OF INFUSIONS, 187 rotatory \motion. In fhort, there is no race whatever which, on diligent examination, does not exhibit motions peculiar to itfelf. If to all this we join the artifice evinced in forming a vortiginous current to entrap their prey: their ferocious purfuit of the fmaller animalcula, their indifference when the ftomach is full, and greedinefs after them when hungry. If we con- fider all the qualities relative to their nature, mo- tion, and properties, not fingle and disjoined, but collected and united in the fame fubject, it is im- poffible not to admit one of two things: either that an infinity of beings recognifed by all the world as real animals are not actually fo; or, if they are, fuch alfo muft be the beings found in infufions. If we refume the ufual mode of analogy, which is the only fupport of accurate judgment, whether a fentient principle refides in animals, and compare the various operations of infufion animalcula with thofe of the largeft animals and ourfelves, we fhall not find them fo diftant or different as not to correfpond in feveral particu- lars. Befides the organization of many animal- cula being fo fimple as to appear nothing but an aggregate of granuli invefted with a fkin, and completely included in it: in fome we fee an af- femblage of parts for the moft oppofite ufes, fuch are fibrilli for a vortex, fins for fwimming, a mouth, "188 ANIMALCULA OF INFUSIONS: {: mouth, an oefophagus, a ftomach, which feems to have a periftaltic motion, agitating the includ- ed aliments. I ought to add another organ I have difcovered in this new courfe of obferva- tions, which I fufpect is deftined for refpiration: It confifts of two ftars, with a very minute globe in the centre, and fituated, as one may fay, in the foci of elliptic animalcula of the largeft or middle fize, Plate :. fig. 11. T. T. Whether - the animalcule moves or not, the ftars are always in alternate and regular motion. Every three or four feconds the minute central globules fwell like a bladder to, three or four times their na- tural fize, and then fall: the inflation and efla- tion are performed very flowly. The fame is done by the rays of the ftars, except that infla. tion of the globes empties the rays, and inflation of the rays empties the globules. During this alternative, a long narrow ellipfe is obferved, in the largeft animalcula, on the fide between the two ftars, in continual motion U. (1). Under this conviction, that the animaltula of infufions are real animals, in addition to the full concurrence of pa{ft and prefent obfervers, ex- cept M. de Buffon, Mr Needham, and a few of their partifans, it gives me inexpreflible pleafure to (1) It is the opinion of feveral naturalifts, that anie malcula have no organs for refpiration, and live without air.—T. 1. ANIMALCULA OF INFUSIONS. x8g to fee myfelf joined by a naturalift, whofe autho« rity, though ftanding fingle, I fhould not hefi- tate to oppofe to that of all Europe. I fpeak of M. de Reaumur, that is of one who, in the ftu- dy of the obfcure kingdom of minute animals, indifputably holds the firft rank among the na- turalifts of the age. In letters to M. Trembley and Bonnet, he thus expreffes himfelf’on the theories of Needham and de Buffon; and, with refpect to the firft, he says, ‘ my object was to £ verity obfervations that had given rife to fuch * {trange ideas of the generation of animals. Dif- “ ferent infufions have been my deepetft ftudy; and * J not only find the imaginary organic molecules ‘real animals, but that they are finular in gene- ‘ ration to others. ‘That thefe animals, according * to the new theory, always become {maller and ‘ fmaller, I have found abfolutely falfe; on the € contrary, all here proceeds by the ordinary rules, ‘ thofe originally {mall at length becoming larg. Cer il) This celebrated perfon exprefies himfelf as de« cifively to M. Bonnet, fignifying that he had re. peated the experiments on the INsEcTs of infu- fions; that he had examined them moft attentive. ly, and for whole hours; and had difcovered what had impofed on thofe who fuppofed them fimple globules in motion. The (7) Corps Organifés, tom. 1, #66 §§ANIMALCULA oF INFUSIONS. t The firft extra& confirms what M. de Sauf- fare and myfelf remarked of the erroneous idea which had induced the belief of the fmaller in- fufion animalcula being generated by others larg. er, and thefe by fome oF ftill a larger fize, ac- cording to M. Needham and de Buffon’s fenti- ments, who have undoubtedly been mifled by a fa€t very feduétive in appearance. It often hap- pens that the whole animalcula of an infufion are of the largeft fize. By an invariable law, the life of animalcula has a determinate period; therefore the largeft perifh in a certain time. Frequently, when they begin to diminifh, a fmall- er fpecies is generated, and thefe are fucceeded by fome ftill fmaller ; laft of all comes a colony of lefs fize than any of the whole. One accul- tomed to explore nature, and to have nothing but her operations in view, will foon perceive there is no relation of parent and offspring among the fucceffive generations. But whoever difdains the trouble of analyfing natural phenomena to the utmoft, and fancies an hypothefis, that the fmaller races proceed from the larger, will readi- ly difcover it in every fucceflive colony of a dif- ferent fize. If, from the reafons adduced, we are conftrained to confider infufior animalcula real animals, what can we anfwer to M. Needham, who conceives himfelf pee to {uppofe them machines fimply vital, ae ANIMALCULA OF INFUSIONS, TOL -vital, and from the fingular caufe, that they pro. pagate by divifion? Firft, 1] fay the author draws a general conclufion from particular faéts, as he _aflumes a general propofition, that all animalcula propagate by divifion. But many others multi- ply without it. The objetion therefore will af- feét only thofe of the firft fpecies; and far from not admitting a plaufible anfwer, it had formerly been advanced by the. partifans of automatifm, when a difcovery was made, that the fections of the polypus became complete animals, as may be feen in Bonnet’s Corps arganifés; which work, if Needham had taken the trouble to per. ufe, would have prevented him from publifhing his obje€tions ; becaufe if in abftrufe and obfcure matters one is contented with probability, as a wife and rational philofopher ought to be, there he would have found enough to his fatisfaGtion. There- fore I adhere to M. Bonnet’s principles, not only becaufe ingenious but juft ; and by their means we can comprehend and explain how the divided parts of an animalcule are transformed into ani- mated and fentient beings. ‘The fact may be e- lucidated by an animal many million times larger than infufion animalcula, by the earth worm, Every fegment becomes a new whole regenerating in itfelf the parts deficient, and among others the head and tail(1). The reproduétion of thefe parts, (1) Prodromo fopra le Reproduzioni Animali, In Ma- dena, 1768, ny ANIMALCULA OF INFUSIONS. Bh parts, and the fame may be faid of the reft, is pro« bably by means of two germs, one deftined to develope into a tail, the other into a head. The foul of the worm when entire refided in the head, admitting in general that it refides there in ami- ‘mals. It will alfo refidein the fame part of the regenerated worm, either becaufe God has cres ated:a new mind, er, as appears more philofophic, becaufe this mid pre-exifted in the germ, and only required evolution to be called into ex- iftence. Behold how the fections of a worm © are reproduced into new and fentient- worms. This with the due proportions may be transferred to infufion animalcula, propagating by natural divifions. Thefe, as far as yet known, may pro- perly be reduced to three kinds, the tran/verfe, dongitudinal, and anomalous, or irregular. By the tranfverfe, the animal feparates into two parts, one the anterior, the other the pofterior. As in the anterior the head remains entire, confequent- ly the foul, that /2/f, that perfonality by which a being may be called animated, » will alfo remain entire. The queftion refts on the pofterior part alone. The progrefs here is the encreafe of this feétion, until it becomes equal to the whole ani- mal; it affumes the figure peculiar to the ani- mal’s head, whether pointed, curved, obtufe, or bell-fhaped, and if the animal is of the number chat produce whirlpools, the points generating a vortex Vat.1. Page 102. é ag UAE Eng? by kirkwood & Son ? sind sa) Do ‘ Hh saul Batak a jee, AAR 3 ‘eh $ ear Sa oh i ; i f ay: ey: Ue G I a +R ised Hy i rv a7 Si a aN } , oF r - . a x a ? Ne i ai 5 ce f. (Te a as I, ANIMALCULA OF INFUSIONS. 193 vortex begin to protrude. Therefore I have good reafon to believe that a new head is developed, and confequently that this whole begins to be ani- mated by a new fentient principle. The theory eafily applies to longitudinal divi- fion, fince it is undoubted that the foul refides in one of the lateral portions, as it refides in the anterior part, where tran{verfe divifion takes place, at the fame time it is certain that the other lateral portion will be fully renewed, as the pofterior part is in tranfverfe divifions, ‘lherefore, if this por- tion expands to form a real animated and fentient being, it is rational to fuppofe the fame will happen to the other. The like may be faid of the anomalouis or ir- regular divifion, by which I mean the divifion of an animal into more than two parts, without be- ing referrible to either the longitudinal or tranf- verfe. Into whatever number of parts it divides, each, in acquiring the fize and figure of the whole, will acquire that perfonality which conftitutes it a teal animal. One part only in thefe irregular di. vifions does not require the developement of a new foul, that is, what formed the original head, as is moft evident: ; Ven, I N Two .* 194 ANIMALCULA OF INFUSIONS! ~ Two EPISTOLARY DISSERTATIONS ON INFUSION: ANIs MALCULA ADDRESSED TO THE AUTHOR BY THE CELEBRATED M. BONNET OF GENEVA. ARGUMENT. Many of the refults in thefe traéts had at dif.’ ferent times been communicated to M. Bonnet, efpecially in two long letters of 20° December 1770, and 15 September 1771. The anfwer to the latter will be found in the Traét on Seminal Vermiculi, and that to the other is the firft of the following. As thefe two letters particularly com- prife the refults on infufion animalcula, it has been judged proper to fubjoin them to the tract: What the reader lias previoufly perufed will en- able him to underftand them properly. According to M. Bonnet’s defire, fome anne- tations have been made by the author, where he felt himfelf neceffitated to be of a different opié nion. And he has been the more induced to it as He knew M. Bonnet was fincere. Thefe let ters, efpecially the fecond, would afford a ftriking inftance of the facility with which- this- great philofopher abandons his opinions, when incon- fiftent with facts, or lefs probable than thofe of another, if his other works did not already de- monftrate it. LET FER, Rew, St ge > f. ANIM ALCULA OF INFUSIONS. igs set ge Ny. LETTER I. om ; My Solitude, 17 anuary 1771. ' THREE of your letters, my illuftrious friend, are before me; the firft dated 23 November, the fe- cond 20 December, and the third 6 January. j owe you a long anfwer, efpecially to the fecond, for it is an exuberant folio replete with new facts, on which it is impoffible to beftow too much re- flection. How much your interefting details have delighted me cannot be defcribed, nor could I refolve to engrofs the whole to myfelf. Meff. Trembley and De Sauflure have participated in the pleafure, and both have been equally fatisfied ; they defire many compliments, with moft — wifhes to you. Their applaufe was certain; and having traverfed thefe unknown regions, they are the. bett judges of your difcoveries. We all three coincide refpecting your létter, and join in the jut culogiums which your ingenuity, accuracy, ‘and correét reafoning merit fo well. Some ideas, excited by that interefting epiftle, were communi: ‘cated to thefe intelligent obfervers, and appeared to give them fatisfaction. I could have wifhed that theirs had been communicated in return, but M. Trembley delays until nature {peaks in more intelligible language ; and M. de Sauffure till he has repeated the experiments. Therefore I fi valk alone run over the principal articles of your NS curious ig6 ANIMALCULA OF INFSSsIONS. J, curious diflertation,. for fuch undoubtedly is the immenfe letter you have taken the trouble to write, and for which accept a thoufand and a thoufand acknowledgements. Kk has been per- ufed with the pen in my hand, and a corrected extract made, that nothing effential might efcape, and that I might be the better enabled to comply with your requeft. It is only difcharging my heavy debt to your friendfhip. I. Your diftribution of infwfions into claffes, diftinguifhed by the time of ebullition, has been moft judicious. By excellent experiments, we are now aflured that two hours boiling does. not pre- vent.the production of animalcula ; we have even reafon to admit that the population of infufions is generally proportioned to the duration of ebul- lition, and the longer it is continued, the more do- animalcula encreafe (1). Here then is enough to. pulverife (1) The meaning of my propofition is: although the leaft boiled infufions had originally few animalcula, com- pared with thofe that- had boiled. more, in time they had immenfe numbers. ‘This greater abundance is naturally explicable by the increafing diffolution of the infufed feeds, becaufe diffolution is a condition moft neceflary for the po- pulation of infufions. M. Bonnet-fuppofes that the addi- tional animalcula may arife from more of them, or their germs, falling into the infufions. Ihave fhewn that his as little probable that animalcula fall from the: air, as it i, ANIMALCULA OF INFUSIONS. 197 pulverife all the fophifms of our obftinate Epige- nefift. The infufions, at farft rarely inhabited, became more populous in time, and you -afcribe it to the gradual diffolution of the infufed matter. As the veflels continued open, one might fay the additional numbers depended on the feeds of ~ animalcula, or en animalcula themfelves preci- pitated from the air, perhaps being attracted by the penetrating odour of the infufion. I do not hefitate to make thefe fuggeftions: you wifh it, and yourfelf difcover many which are familar, in your inveftigations of nature. N 3 ii. it is certain their germs do fo. Whence 1 have no doubt that the animalcula, whofe numbers increafe with the lapie of time, partly originate from new germs precipitated into the veffels. However it cannot be thought, that the accef- fion of thefe germs alone is equal to the additional popula- tion, otherwife an equal quantity having fallen into the infufions that had boiled much, as into tkofe that had not, there is no reafon why the animalcula of the firft fhould be abundant in afew days, and thofe of the fecond only after aninterval of many. A difference fo fenfible mutt depend on fome fecret condition, and I can fee none other than decompofition of the infufed fubftances which takes place as much fooner in the infufions boiled much, az later in thofe that have boiled little. 198 .ANIMALCULA OF INFUSIONs. I, Ii. It was already important to fee thoufands _of animalcula in every kind of infufion boiled two hours ; but fudftances were expofed to a trial ftill ‘more fevere, by roafting them in metallic cups, and then forming powders of which you compo- fed infufions with boiled water. All fwarmed -with animalcula of every fize and defcription. Af ter this, how can we refufe our affent to the ge- ‘meral conclufions which you deduce from fuch decifive experiments? How can we refufe to agree, that the vegetative or productive power of our friend the Epigenefift is a ‘perfe&t chimera ? He objects that too great heat in your firft experi- ments might have deftroyed the productive power of the matter infufed ; yet, when expofed to much greater heat, it was ftill inhabited by numerous animated beings (1). If the obftinacy of our friend is not invincible, he will yield to firch evi- dence. Il. It feems rigoroufly demonftrated by your experiments, that animalcula appear in fubftances included in veffels hermetically fealed, and expo- fed ten minutes to the influence of boiling water before inclufion. But the reafon why as many animalcula are not exhibited in clofe as in open velfels, we may infer to be, becaufe the excefs in the latter arifes from the feeds of animalcula and anl- (1) It is already feen how much heat was increafed. I. ANIMALCULA OF INFUSIONS. 199 animalcula themfelves precipitated from the ex- ternal air. Perhaps the communication of the 4ubftances with the air may alfo facilitate their. dif- dolution, and the eaueraiion of animalcula in:con- ‘fequence. IV. By the cleareft sappadivbaads you have happily refuted an important objection, that the al- tered {tate of the air in the veflels had prejudiced the vegetative power -of fubftances infufed ; but animalcula continued to appear in veflels herme- tically fealed expofed to boiling heat, fome from half 4 minute to two minutes, others from fix mi- nutes to twelve(1). The fmalleft. animalcula only originate, and none of the largeft or middle fized. Thus it feems fufficiently. proved, that thofe of the higher clafs cannot originate or ex- pand in fubftances fubjeéted te fimilar experi- ‘ments. A fact which may be-the fubject of the moft profound meditation is demonftrated: the dmaller the animalcula are, the lefs injurious is cheat to their generation or developement.. -I fhall foon return to this. If the higher claffes are not feen in veffels hermetically fealed, and expof- ed half a minute to beiling heat, cannot we ‘thence conclude, that all the animalcula you have {een fo numerous in infufions boiled from.half an Ni 4, 33 hour (1) Ebullition above twelve minuteshas not obftru@ed _ fhe production of the fmalleft animalcula. 200 ANIMALCULA OF INFUsIONS. JI, hour to two hours, that thefe animalcula, I fay, or part of them, may come from the external air, from that in the veffels or the feeds attached to their fides, or from all three? This conclufion eems the more probable concerning the higher claffes. Indeed, if we fuppofe that they or their feeds lodged in the infufed matter, there is no reafon why they fhould not appear in yeflels her- metically fealed, and expofed to the heat of boil- ing water, if that degree was not prejudicial to their appearance. You have proved that they are ftill feen in fealed veffels of infufions, which have not been expofed to heat. ‘The higher clafs, poe did not pre-exift in the infufed matter: But I do not thence mean to infinuate, that they or their germs could not pre-exift in it, for animal and vegetable fubftances are probably covered with them. I only mean, that thefe ani- yalcula, or their germs, are probably deftroyed by boiling the fubftances where they are lodged, Are you not furprifed, my dear friend, that I do pot fay certainly deftroyed ? But I dare not make fuch a pofitive affertion concerning beings fo little known. Is it not poflible, that the heat of boile ing water, or any other of equal or even greater degree, produces no effect but deficcation of ani- -malcula or their germs, and thus reduces them to a ftate analogous to that of pennated polypi’s eggs, which may be kept dry feyeral months, as | I. ANIMALCULA OF INFUSIONS. 201 Ihave obferved, Article 317 of the Corps Orga. aisés? After having boiled veffels hermetically fealed with various infufed matter, I with you would let it cool in the fame veffels, and make obfervations to difcover whether the animalcula gradually appear. ‘This fimple experiment may be very inftructive (1). : V. By your letter, 1 perceive that the animal. cula of what you term the mediate and higheft clafs, which are here more briefly defigned of the higher (1) My anfwer to M. Bonnet is thus exprefled: * The experiment which you, my illuftrious friend, propofed, had already been made in part, although the fole object on a at the time was to examine whether veffels hermetically fealed, and expofed to the influence of heat, would afford ~ more or fewer animalcula in proportion as I delayed to obferve them. Therefore, on 26 September 1770, eleven veflels were boiled, and the feals broke g Odober; they contained only the moft minute animalcula: five more were opened October 13: they had none but the fame animalcula. ‘Thus the prolongation of time had no ~ an ~~ influence on the production of the largeft animalcula.? Brevity prevents me from relating another experiment, where the effect was fimilar. We have already feen, that protraction of time did not favour the production of the largeft animalcula, or higheft clafs, in veffels hermetically fealed and expofed toheat. I think there is reafon to con- clude, that the heat of boiling water really deftroys the germs of the higher clafles, 202 ANIMALCULA OF INFUSIONS. . higher orders, 1 perceive, I fay, that thefe ani- amalcula cannot expand at 174°, but want of time prevented the extenfion of your refearches on this point. It would be very defirable to af- ‘certain the degree, or to come near it, at which they may be developed(1); and it would be ufe- ful to afcertain how much cold they can fuftain. All this would have fome tendency to elucidate the fingular conftitution of thefe living beings, and afford us comparifons and inductions which might throw fome light on fo obfcure a part of the animal kingdom. ‘The evolution of ani- mals is evidently proportioned to the heat necef- fary for putting their fluids in motion, and for extenfion of their veffels. The earlieft plants are apparently thofe whofe liquids are put in mo- tion by the leaft degree of heat, and whofe vei- fels afford but little refiftance to gentle impref- fions of their fluids. The life of many infects may be abridged or prolonged by keeping them in cold or warm fituations, Corps Organisés, Art. 167; and we know there are infects that can fupport the cold of 14 or 15° of Reaumur’s thermometer, and remain alive though complete- ly (1) By experiments afterwards inflituted, I was able te fix the precife degree. I, ANIMALCULA OF INFUSIONS. 203 dy frozen (1). To the celebrated Reaumur are we indebted for our knowledge of this part of the animal economy. In January 1767, I repeated the curious: experiments with frozen infeéts. _Chryfalids of the beautiful cabbage caterpillar were expofed to 12 or 13°(2); they feemed completely frozen; and, when dropt into a china veffel, founded like a ftone. But they were not _ dead; and, towards the middle of May, the butterfly appeared, nor was the transformation -dater than of others of the fame fpecies that had pafled winter and part of fpring on the ftove of my apartment. Infufion animalcula might in this way prefent much more furprifing facts : we have only to invent experiments fit to difcover them. The fubject is too interefting not to ex- cite the curlofity of a naturalift as intelligent as you (3). ' VI. {1) M. Bonnet means thefe degrees below freezing ; becaufe the feale of Reaumur’s thermometer begins at the freezing point, or 32 of Fahrenheit’s; therefore 14 will be nearly 0, and 15 about two below o of Fah- renheit’s.—T, (2) About 5 and 3 of Fahrenheit.—T. (3) My anfwer to M. Bonnet informed him that I had " anticipated the experiment he fuggefts; but that the com- munication was referved until I had obtained enough of facts. Thefe are detailed in the Tract. 204 ANIMALCULA OF INFUSIONS. {J Vi. I now come to that article of your letter which has given me the moft agreeable furprife, and affords moft ample matter for reflection. You have completely proved that the fmalleft animalcula, or thofe I denominate the lowe clafs, originate and expand in infufions expofed from half a minute to twelve minutes to the effects of boiling water, in veffels hermetically fealed ; while it is at the fame time demonftrated that the animalcula themfelves perifhed at 106 and 108°. Here undoubtedly is a moft important fa& which philofophers would never have fufpeéted without deep meditation on the nature of germs, and their analogy with the elements. This ex- cellent difcovery has given me much pleafure: it feems to corroborate my fentiments concerning germs; and the reflections which it has excited fhall be fubmitted to your opinion. You know, my dear friend, that the more dia- phanous a body is, the lefs is it heated by the rays of the fun; and the greater the number of pores, the more open and direé, the lefs do the rays act on their fides. The celebrated Bouguer reafonably attributes the exceflive cold felt on the higheft mountains to the extreme rarity of the air admitting too free paflage to the folar rays for them to make any fenfible impreffion on this fluid. It is eafy to conceive that fome bodies may exift, fo thin, homogeneous, and perfe¢tly diapha- nous, I,