BACTERIOLOGICAL RzvIEws, Mar. 1976, p. 241-258 Copyright 0 1976 American Society for Microbiology
Vol. 40, No. 1 Printed in U.SA.
Louis Joblot and His Microscopes HUBERT LECHEVALIER Waksman Institute of Microbiology, Rutgers University, The State University ofNew Jersey, New Brunswick, New Jersey 08903
INTRODUCTION .................. JOBLOT'S BOOK .................. Selections from Part I .................. Selections from Part II .................. CONCLUSION ..................... LITERATURE CITED ..................
INTRODUCTION Louis Joblot was born in 1645 in Bar-le-Duc, a small town located where Lorraine and Champagne meet in the picturesque valley of Ornain. He died in Paris in 1723. During his life, Joblot was engaged primarily in the study of physics: magnetism and optics had a special fascination for him. It is mainly because of his microscopes and what he saw with them that we remember him. Louis Joblot was a contemporary of Antony van Leeuwenhoek, both men dying in the same year. The details of the life of Joblot have been poorly documented, and what little we know was religiously assembled by a certain Wlodimir Konarski who buried his work in an obscure journal, published in 1895, dedicated to the local history of Joblot's native town, Bar-leDuc (12). Louis Joblot was baptized on August 9, 1645. His parents were probably local merchants of some wealth. How and when he found his way to Paris is not known, but in 1680, he was appointed assistant to the well-known engraver Sebastien Le Clerc (1637-1714) to teach geometry to the students of the Royal Academy of Painting and Sculpture. This position carried no salary, and we must assume that Joblot was either independently wealthy or had some other source of income, possibly from giving private lessons in mathematics. In 1697, he requested a leave of absence of 15 to 18 months to travel in Italy, the cradle ofthe arts. In 1699, he was appointed Professor of Perspective and Geometry, replacing Le Clerc. In his lectures, he stressed the mechanism of vision and even indulged in the dissection of eyes. He was then entitled to a salary of 300 pounds a year, which was less than that paid by the Academy to a model! In 1717, it was his turn to request the appointment of an assistant, and four years later he retired, retaining the title of Counselor and Professor Emeritus. He died on April 27, 1723.
241 242 243 248 256 258
This is the extent of the hard facts that we have concerning the life of Joblot. To this we might add that he was probably not married, that he associated with those interested in science, delighting them with experiments and demonstrations in the field of magnetism and microscopy, and that he lived in that part of Paris where makers of precision instruments were concentrated. Joblot interests us because of a book that he published in 1718, which was entitled Descriptions and Uses of Several New Microscopes, Both Simple and Compound (Descriptions et Usages de Plusieurs Nouveaux Microscopes tant Simples que Composez). Part of it was translated into English by Adams in 1746 (1). Joblot's book was republished in 1754 and 1755 in two volumes entitled Natural History Observations Made with the Microscope (Observations d'Histoire Naturelle Faites avec le Microscope). The publisher, Briasson, had bought the plates of Joblot's book and had added some material of little importance, mainly on insects, to the original text in order to make a "new book." For obvious reasons, the second edition of Joblot's book never received the author's blessing and was simply a device to make money for M. Briasson. Jean Senebier (14) of Geneva refers to Joblot's book in the introduction to his 1787 French translation of Spallanzani's Opuscoli di Fisica Animale e Vegetabile. After that, Dujardin (1841) (9) wrote: "Joblot, in 1754, published microscopic observations which were rather good for the time, and which are not without value, in spite of the ridiculous names used...." Dujardin did not seem to be aware of the fact that the 1754 edition was only, as far as microbiology is concerned, a reproduction of the 1718 edition. If Joblot's observations were good for 1754, they must have been outstanding for 1718! Dujardin's error was pointed out by Fleck in 1876 (10). In 1894, Cazeneuve (5) explained how he had read the 1754 French translation of Henry 241
242
LECHEVALIER
Baker's book on the microscope originally published in 1743, and how he had been impressed by Baker's ideas on spontaneous generation. He noted that Baker referred to Joblot several times. Subsequently Cazeneuve was able to get hold of the second edition of Joblot's book, from which he quoted key passages. From then on, the scientific world was to be aware of Joblot's important contributions. Boyer (1894) (4), who had the good fortune of owning a copy of the original Descriptions of Joblot, published some additions and corrections to Cazeneuve's comments. One year later, Konarski (12) published his comprehensive study on Joblot. In 1923, Dobell (7) compared the protozoological contributions of the two pioneers who had passed away two centuries previously: Leeuwenhoek and Joblot. A few pages of Joblot's book were reprinted by Woodruff in 1937 (16). Since the original edition of Joblot's book and Adams' translation of selected passages are rarities that few persons will ever have the chance to see, I have included a sampling of Joblot's illustrations, together with enough of his text in translation, to give the flavor of the book. In making a fresh translation of Joblot's text, I have taken care to follow the spirit and style of the French of his time. To appreciate the importance of Joblot's book, it is enough to remember that it is the first separate treatise on microorganisms, one in which some protozoa are illustated for the first time, and that it contains the first experiments ever made to disprove spontaneous generation of microorganisms by heat sterilization. To this, I could add that this book probably contains the first reference to the use of a shaking machine in a microbiological process. JOBLOT'S BOOK Descriptions and uses of several new microscopes both single and compound with new observations made on an innumerable multitude of insects and other animals of various species, which are born in natural and prepared liquors. By L. Joblot, Royal Professor of Mathematics at the Royal Academy of Painting and Sculpture, living on the Quay of the Clock of the Palace, at the large Grape.' in Paris At Jacques Collombat, Printer ordinary of the King, and of the Royal Academy of Painting and Sculpture, Saint Jacques Street at the Pelican' Houses, at that time in Paris, often had signs used to refer to them as we now use numbers. '
BACTERIOL. REV. MDCC XVIII With the consent and authorization of the King
PREFACE One part of this work is no more, so to speak, than a sort of a Journal of the observations that I have made on an infinite multitude of very small animals which are beyond the ordinary range of our vision. The ease of utilization of my new microscopes has imperceptibly led me farther than I had planned and forced me into details that might appear dull to those who are not accustomed to following nature in its workings.... I have added to my observations conjectures on the production of various species of small animals which are found in liquors. I cannot share the opinion of those who attribute them to putrefaction; this idea is hard to accept since it would mean abandoning to the irregularity of chance Works which are always accomplished with an order that one cannot cease to admire. I have thus substituted another concept which seems to fit clearly with the almost infinite multitude of all my experiments. I have divided this work into two parts: the first contains the construction and uses of several Microscopes which are most convenient and more perfect than any of those that have so far come to my attention. One can see them in perspective on twenty-two plates,' with the plans and profiles necessary for good understanding of their mechanisms and use. There are two or three of these microscopes which have almost universal application.. .On such an instrument one will be able to mount easily and rapidly, not only lenses of various foci, but also very small microscopes with two and three lenses which are from one to three inches long, the shorter ones having considerable advantages, such as letting one observe objects in their natural, upright position.... And to ... a ... universal microscope one will be able, very easily and without difficulty, to apply fishes of various species such as tadpoles, frog, lampreys, eels, ... minnows etc.' in the tail of which, and other places, one will have the pleasure of seeing the various movements of blood in variously curved vessels... ... I have furnished several Microscopes to renowned Physicians, famous Anatomists, and to several other illustrious amateurs in these novelties, and it is almost impossible that each one of them, while pleasantly occupied with the examination of the surprising effects of nature, will not discover every day new and singular things, which they will be able to communicate to the Public both by the means of private ' Three of these are reproduced here. ' These animals were held in a tube in such a way that their tail was brought in focus of the lens.
VOL. 40, 1976
lectures and by publication in the "Journaux des Scavans".... The second Part of this Book contains twelve Plates' ... by means of which are illustrated a portion of the new discoveries that we have made.... I have been able to describe the small animals which are found in the infusions discussed in the second Part, only by giving them differentiating names. To this end I have looked for things in nature which are rather well known and which would have some resemblance to the fishes that I have seen in my liquors... Limited by my lack of knowledge ofthe various beings of nature, I have been forced to name other fishes differently, by giving them names which, in some way, marked their particular inclinations, or their most common movements. Thus, I have named some Bagpipes, Ovals, Aquatic caterpillars, Funnels, Crested hens, Kidneys, etc. To others I have given the names of Blind ones, Somersaulters, Gobblers, Fickles, Buffoons, El-
egants, etc....
From this introduction, in which the author states that he has borne the cost of the publication of the book, it is quite obvious that Joblot, a professor, unlike Leeuwenhoek, an amateur (7), was most interested in sharing his work with others, not only his results, but also his
methods.
Selections from Part I This first part of Joblot's book, appropriately entitled: "Description of the microscopes that I have used," starts with the apology that before he could relate his observations: ... It was necessary to describe all the parts of the instruments that I have used in these investigations. Those who have a taste for these discoveries will be able to verify my experiments by themselves and will be able to push them farther than I have done.
The technical description of the microscopes is prefaced with the warning that: Each microscope seems to me to have properties that make it suitable only for certain uses. Thus, I do not think that one could invent one which would have all the properties of those that I shall propose....
The microscopes described by Louis Joblot range from simple magnifying glasses variously mounted (Fig. 1) to compound microscopes with four lenses (Fig. 2). Joblot distinguishes those microscopes that were especially made for the observation of liquors from those made to observe specimens held ' Four of these are reproduced here.
LOUIS JOBLOT'S MICROSCOPES
243
at the end of pins or clamps. Another type is a cylindrical glass chamber within which small animals can be observed for prolonged periods of time (Fig. 3). These are called "graves," since animals often died there during the period of observation. Finally, the "universal microscopes" are those with attachments permitting the observation of "all sorts of small objects; hard, soft and all that can be seen in liquids." The descriptions of Joblot's microscopes are very detailed as far as the mechanical parts are concerned, but no details are given on how the lenses were made; the only references made to the optical properties of the lenses are their focal lengths. In one case, the lens is referred to as having been blown (i.e., of blown glass); by implication, this would indicate that all the other lenses were ground. At one point, the use of a lathe in polishing or cutting lenses is mentioned. Not many microscopes exist of the types Joblot designed, and it is entirely possible that not one of the original microscopes that he owned has survived. The Royal Microscopical Society has an example of one of the microscopes designed by Joblot (2). It is inscribed, "J. Langlois, Eleve du Sieur Butterfield, aux Armes d'Angleterre, a Paris" and is also described and illustrated by Clay and Court (6). It is a universal microscope. Another less ornate Joblot-type microscope, also illustrated by Clay and Court, is now at the Museum of the History of Science in Oxford. In addition, two Joblot-type microscopes are in the Nachet Colection in Paris. On pages 6 and 53 of Part I, Joblot notes that some of his microscopes, at least, were built by "Monsieur Le Febvre, an engineer [who was] very skillful in the construction of mathematical instruments." In Joblot's book, details are also given on the use of the microscopes, the placement of the specimen, and the types of subjects recommended for observation. Blood circulation was one of his favorites: in more than one place he gives instructions for the observation of capillary circulation. The use of slides, depression slides, and cover slips is also discussed. As can be seen in Fig. 2, diaphragms were used extensively. It is entirely possible that they may have been an original invention of Joblot's, and they certainly improved the quality of the images that he saw. On the basis of the focal distances given by Joblot, Konarski (12) concluded that his most powerful microscopes may have been capable of magnifying some 400x, essentially double the power of Leeuwenhoek's instruments.
244
BACTERIOL. REV.
LECHEVALIER
i
Oee-ewdvat d2ort& he om&.
I1
-P-3
I. FIG. 1. Translation: "Drawing of a magnifying glass-carrier."
Among the simple things that one could observe, grains of sand, on which vinegar eels (Nematodes) could be placed, were recommended. ... But if on these same grains of sands you let fall a small drop of vinegar in which there are eels, they will furnish you with a new amusing spectacle, because of the straits in which they find themselves as they try to get free of the masses of rocks formed by the grains of sand falling on their bodies and by the shaking the eels give the grains of sand as they push them apart, to make a free passage.
Concerning flies: one can easily examine all their exterior parts and thus discover the error of ancient
Philosophers, and even of a few modern ones, who think that flies cling to bodies on which they walk only because a kind of sticky humor oozes continuously from their feet.... Glass cylinder microscopes, which some persons refer to as tombs or cemeteries of various animals [Fig. 3] . .. are very useful to observe a part of what is going on, both in living and dead animals ranging in size from that of a flea to that of a June beetle. ... ... One usually despises insects and other small animals which men believe owe their birth to decaying matter; but it is easy to show that this scorn is unfair and that it is based only on ignorance.... The smallest gnats are as perfect as the largest animals: the proportions of their members are as good as those of others; and it even seems that God has wanted to give them more ornaments than he gave to the
LOUIS JOBLOT'S MICROSCOPES
VOL. 40, 1976
245
yr-a'
A
B
~~~~~~4
4
k
Vol. 40, No. 1 Printed in U.SA.
Louis Joblot and His Microscopes HUBERT LECHEVALIER Waksman Institute of Microbiology, Rutgers University, The State University ofNew Jersey, New Brunswick, New Jersey 08903
INTRODUCTION .................. JOBLOT'S BOOK .................. Selections from Part I .................. Selections from Part II .................. CONCLUSION ..................... LITERATURE CITED ..................
INTRODUCTION Louis Joblot was born in 1645 in Bar-le-Duc, a small town located where Lorraine and Champagne meet in the picturesque valley of Ornain. He died in Paris in 1723. During his life, Joblot was engaged primarily in the study of physics: magnetism and optics had a special fascination for him. It is mainly because of his microscopes and what he saw with them that we remember him. Louis Joblot was a contemporary of Antony van Leeuwenhoek, both men dying in the same year. The details of the life of Joblot have been poorly documented, and what little we know was religiously assembled by a certain Wlodimir Konarski who buried his work in an obscure journal, published in 1895, dedicated to the local history of Joblot's native town, Bar-leDuc (12). Louis Joblot was baptized on August 9, 1645. His parents were probably local merchants of some wealth. How and when he found his way to Paris is not known, but in 1680, he was appointed assistant to the well-known engraver Sebastien Le Clerc (1637-1714) to teach geometry to the students of the Royal Academy of Painting and Sculpture. This position carried no salary, and we must assume that Joblot was either independently wealthy or had some other source of income, possibly from giving private lessons in mathematics. In 1697, he requested a leave of absence of 15 to 18 months to travel in Italy, the cradle ofthe arts. In 1699, he was appointed Professor of Perspective and Geometry, replacing Le Clerc. In his lectures, he stressed the mechanism of vision and even indulged in the dissection of eyes. He was then entitled to a salary of 300 pounds a year, which was less than that paid by the Academy to a model! In 1717, it was his turn to request the appointment of an assistant, and four years later he retired, retaining the title of Counselor and Professor Emeritus. He died on April 27, 1723.
241 242 243 248 256 258
This is the extent of the hard facts that we have concerning the life of Joblot. To this we might add that he was probably not married, that he associated with those interested in science, delighting them with experiments and demonstrations in the field of magnetism and microscopy, and that he lived in that part of Paris where makers of precision instruments were concentrated. Joblot interests us because of a book that he published in 1718, which was entitled Descriptions and Uses of Several New Microscopes, Both Simple and Compound (Descriptions et Usages de Plusieurs Nouveaux Microscopes tant Simples que Composez). Part of it was translated into English by Adams in 1746 (1). Joblot's book was republished in 1754 and 1755 in two volumes entitled Natural History Observations Made with the Microscope (Observations d'Histoire Naturelle Faites avec le Microscope). The publisher, Briasson, had bought the plates of Joblot's book and had added some material of little importance, mainly on insects, to the original text in order to make a "new book." For obvious reasons, the second edition of Joblot's book never received the author's blessing and was simply a device to make money for M. Briasson. Jean Senebier (14) of Geneva refers to Joblot's book in the introduction to his 1787 French translation of Spallanzani's Opuscoli di Fisica Animale e Vegetabile. After that, Dujardin (1841) (9) wrote: "Joblot, in 1754, published microscopic observations which were rather good for the time, and which are not without value, in spite of the ridiculous names used...." Dujardin did not seem to be aware of the fact that the 1754 edition was only, as far as microbiology is concerned, a reproduction of the 1718 edition. If Joblot's observations were good for 1754, they must have been outstanding for 1718! Dujardin's error was pointed out by Fleck in 1876 (10). In 1894, Cazeneuve (5) explained how he had read the 1754 French translation of Henry 241
242
LECHEVALIER
Baker's book on the microscope originally published in 1743, and how he had been impressed by Baker's ideas on spontaneous generation. He noted that Baker referred to Joblot several times. Subsequently Cazeneuve was able to get hold of the second edition of Joblot's book, from which he quoted key passages. From then on, the scientific world was to be aware of Joblot's important contributions. Boyer (1894) (4), who had the good fortune of owning a copy of the original Descriptions of Joblot, published some additions and corrections to Cazeneuve's comments. One year later, Konarski (12) published his comprehensive study on Joblot. In 1923, Dobell (7) compared the protozoological contributions of the two pioneers who had passed away two centuries previously: Leeuwenhoek and Joblot. A few pages of Joblot's book were reprinted by Woodruff in 1937 (16). Since the original edition of Joblot's book and Adams' translation of selected passages are rarities that few persons will ever have the chance to see, I have included a sampling of Joblot's illustrations, together with enough of his text in translation, to give the flavor of the book. In making a fresh translation of Joblot's text, I have taken care to follow the spirit and style of the French of his time. To appreciate the importance of Joblot's book, it is enough to remember that it is the first separate treatise on microorganisms, one in which some protozoa are illustated for the first time, and that it contains the first experiments ever made to disprove spontaneous generation of microorganisms by heat sterilization. To this, I could add that this book probably contains the first reference to the use of a shaking machine in a microbiological process. JOBLOT'S BOOK Descriptions and uses of several new microscopes both single and compound with new observations made on an innumerable multitude of insects and other animals of various species, which are born in natural and prepared liquors. By L. Joblot, Royal Professor of Mathematics at the Royal Academy of Painting and Sculpture, living on the Quay of the Clock of the Palace, at the large Grape.' in Paris At Jacques Collombat, Printer ordinary of the King, and of the Royal Academy of Painting and Sculpture, Saint Jacques Street at the Pelican' Houses, at that time in Paris, often had signs used to refer to them as we now use numbers. '
BACTERIOL. REV. MDCC XVIII With the consent and authorization of the King
PREFACE One part of this work is no more, so to speak, than a sort of a Journal of the observations that I have made on an infinite multitude of very small animals which are beyond the ordinary range of our vision. The ease of utilization of my new microscopes has imperceptibly led me farther than I had planned and forced me into details that might appear dull to those who are not accustomed to following nature in its workings.... I have added to my observations conjectures on the production of various species of small animals which are found in liquors. I cannot share the opinion of those who attribute them to putrefaction; this idea is hard to accept since it would mean abandoning to the irregularity of chance Works which are always accomplished with an order that one cannot cease to admire. I have thus substituted another concept which seems to fit clearly with the almost infinite multitude of all my experiments. I have divided this work into two parts: the first contains the construction and uses of several Microscopes which are most convenient and more perfect than any of those that have so far come to my attention. One can see them in perspective on twenty-two plates,' with the plans and profiles necessary for good understanding of their mechanisms and use. There are two or three of these microscopes which have almost universal application.. .On such an instrument one will be able to mount easily and rapidly, not only lenses of various foci, but also very small microscopes with two and three lenses which are from one to three inches long, the shorter ones having considerable advantages, such as letting one observe objects in their natural, upright position.... And to ... a ... universal microscope one will be able, very easily and without difficulty, to apply fishes of various species such as tadpoles, frog, lampreys, eels, ... minnows etc.' in the tail of which, and other places, one will have the pleasure of seeing the various movements of blood in variously curved vessels... ... I have furnished several Microscopes to renowned Physicians, famous Anatomists, and to several other illustrious amateurs in these novelties, and it is almost impossible that each one of them, while pleasantly occupied with the examination of the surprising effects of nature, will not discover every day new and singular things, which they will be able to communicate to the Public both by the means of private ' Three of these are reproduced here. ' These animals were held in a tube in such a way that their tail was brought in focus of the lens.
VOL. 40, 1976
lectures and by publication in the "Journaux des Scavans".... The second Part of this Book contains twelve Plates' ... by means of which are illustrated a portion of the new discoveries that we have made.... I have been able to describe the small animals which are found in the infusions discussed in the second Part, only by giving them differentiating names. To this end I have looked for things in nature which are rather well known and which would have some resemblance to the fishes that I have seen in my liquors... Limited by my lack of knowledge ofthe various beings of nature, I have been forced to name other fishes differently, by giving them names which, in some way, marked their particular inclinations, or their most common movements. Thus, I have named some Bagpipes, Ovals, Aquatic caterpillars, Funnels, Crested hens, Kidneys, etc. To others I have given the names of Blind ones, Somersaulters, Gobblers, Fickles, Buffoons, El-
egants, etc....
From this introduction, in which the author states that he has borne the cost of the publication of the book, it is quite obvious that Joblot, a professor, unlike Leeuwenhoek, an amateur (7), was most interested in sharing his work with others, not only his results, but also his
methods.
Selections from Part I This first part of Joblot's book, appropriately entitled: "Description of the microscopes that I have used," starts with the apology that before he could relate his observations: ... It was necessary to describe all the parts of the instruments that I have used in these investigations. Those who have a taste for these discoveries will be able to verify my experiments by themselves and will be able to push them farther than I have done.
The technical description of the microscopes is prefaced with the warning that: Each microscope seems to me to have properties that make it suitable only for certain uses. Thus, I do not think that one could invent one which would have all the properties of those that I shall propose....
The microscopes described by Louis Joblot range from simple magnifying glasses variously mounted (Fig. 1) to compound microscopes with four lenses (Fig. 2). Joblot distinguishes those microscopes that were especially made for the observation of liquors from those made to observe specimens held ' Four of these are reproduced here.
LOUIS JOBLOT'S MICROSCOPES
243
at the end of pins or clamps. Another type is a cylindrical glass chamber within which small animals can be observed for prolonged periods of time (Fig. 3). These are called "graves," since animals often died there during the period of observation. Finally, the "universal microscopes" are those with attachments permitting the observation of "all sorts of small objects; hard, soft and all that can be seen in liquids." The descriptions of Joblot's microscopes are very detailed as far as the mechanical parts are concerned, but no details are given on how the lenses were made; the only references made to the optical properties of the lenses are their focal lengths. In one case, the lens is referred to as having been blown (i.e., of blown glass); by implication, this would indicate that all the other lenses were ground. At one point, the use of a lathe in polishing or cutting lenses is mentioned. Not many microscopes exist of the types Joblot designed, and it is entirely possible that not one of the original microscopes that he owned has survived. The Royal Microscopical Society has an example of one of the microscopes designed by Joblot (2). It is inscribed, "J. Langlois, Eleve du Sieur Butterfield, aux Armes d'Angleterre, a Paris" and is also described and illustrated by Clay and Court (6). It is a universal microscope. Another less ornate Joblot-type microscope, also illustrated by Clay and Court, is now at the Museum of the History of Science in Oxford. In addition, two Joblot-type microscopes are in the Nachet Colection in Paris. On pages 6 and 53 of Part I, Joblot notes that some of his microscopes, at least, were built by "Monsieur Le Febvre, an engineer [who was] very skillful in the construction of mathematical instruments." In Joblot's book, details are also given on the use of the microscopes, the placement of the specimen, and the types of subjects recommended for observation. Blood circulation was one of his favorites: in more than one place he gives instructions for the observation of capillary circulation. The use of slides, depression slides, and cover slips is also discussed. As can be seen in Fig. 2, diaphragms were used extensively. It is entirely possible that they may have been an original invention of Joblot's, and they certainly improved the quality of the images that he saw. On the basis of the focal distances given by Joblot, Konarski (12) concluded that his most powerful microscopes may have been capable of magnifying some 400x, essentially double the power of Leeuwenhoek's instruments.
244
BACTERIOL. REV.
LECHEVALIER
i
Oee-ewdvat d2ort& he om&.
I1
-P-3
I. FIG. 1. Translation: "Drawing of a magnifying glass-carrier."
Among the simple things that one could observe, grains of sand, on which vinegar eels (Nematodes) could be placed, were recommended. ... But if on these same grains of sands you let fall a small drop of vinegar in which there are eels, they will furnish you with a new amusing spectacle, because of the straits in which they find themselves as they try to get free of the masses of rocks formed by the grains of sand falling on their bodies and by the shaking the eels give the grains of sand as they push them apart, to make a free passage.
Concerning flies: one can easily examine all their exterior parts and thus discover the error of ancient
Philosophers, and even of a few modern ones, who think that flies cling to bodies on which they walk only because a kind of sticky humor oozes continuously from their feet.... Glass cylinder microscopes, which some persons refer to as tombs or cemeteries of various animals [Fig. 3] . .. are very useful to observe a part of what is going on, both in living and dead animals ranging in size from that of a flea to that of a June beetle. ... ... One usually despises insects and other small animals which men believe owe their birth to decaying matter; but it is easy to show that this scorn is unfair and that it is based only on ignorance.... The smallest gnats are as perfect as the largest animals: the proportions of their members are as good as those of others; and it even seems that God has wanted to give them more ornaments than he gave to the
LOUIS JOBLOT'S MICROSCOPES
VOL. 40, 1976
245
yr-a'
A
B
~~~~~~4
4
k
