ing ile st eee Shh, ». ah ey ’ du TT, mor ay 7 Goruell University Library Sthaca, New York GEORGE FRANCIS ATKINSON * BOTANICAL LIBRARY 1920 LIBRARY —|THACA, N.Y, Cornell University Library QR 56.T85 wii Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003199159 THE INTERNATIONAL SCIENTIFIC SERIES VOLUME LVI THE INTERNATIONAL SCIENTIFIC SERIES. Eacu Book COMPLETE IN OwE Votoms, 12M0, AND BOUND IN CrorTu. 1, FORMS OF WATER: A Familiar Exposition of the Origin and Phe- nomena of Glaciers. By J. Tynpany, LL.D., F.R.S. With 25 Illustrations. $1.50. 2, PHYSICS AND POLITICS; Or, Thoughts on the Application of the Principles of ‘‘ Natural Selection’? and ‘Inheritance’? to Political Society. By Waxrer Bacenor. $1.50. 3. FOODS. By Epwarp Surra, M.D., LL. B., F.R.S. With numerous Tlustrations. $1.75. 4. 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D., F.L.8., Barrister-at-Law ; Professor of Clas- sics and English Literature, University College, Auckland, New Zealand, author of “‘ The Historical Method,” etc. $1.75. EARTHQUAKES AND OTHER EARTH MOVEMENTS. By Joun Mune, Professor of Mining and Geology in the Imperial College of Engineering, Tokio, Japan. With 88 Figures, $1.75. New York: D. APPLETON & CO., 1, 8, & 5 Bond Street. THE INTERNATIONAL SCIENTIFIC SERIES MICROBES FERMENTS AND MOULDS BY E. L. TROUESSART WITH ONE HUNDRED AND SEVEN ILLUSTRATIONS NEW YORK D. APPLETON AND COMPANY 1, 8, anv 5 BOND STREET 1886 aR ss see @ L422 PREFACKH. —~ — THE number of works which treat of microbes is already considerable, but they have all been written for a special public of physicians or naturalists, and imply that the reader is familiar with the ideas already established on pathology or on cryptogamic botany. Although the science of microbes is of recent origin, it has made immense progress in the course of a few years. It is, moreover, essentially a French science, since it is owing to Pasteur’s admirable labours, as well as to his solid genius, aided by the faith and energy of his disciples, that this science has been able to overcome the prejudices of ages, and to penetrate into the very heart of the ancient theory of medicine, so as to transform and regenerate it. ” Every one now speaks of microbes, yet few of those who make use of the term have any clear conception vi PREFACE. of the beings in question, or could give an exact account of the function which microbes fulfil in nature.. And yet this function concerns us all. The man of the world who desires to take part in a scientific discussion; the lawyer who has to treat of a question of hygiene in the presence of experts; the engineer, the architect, the manufacturer, the agricul- turist, the administrator—all have to consider such questions, and they will find in this work clear and precise notions on microbes, notions which they would find it difficult to glean from books designed for physicians and professional botanists, The questions of practical hygiene, those which concern domestic economy, agriculture, and manufac- tures, and which are connected with the study of microbes, must especially demand attention. These are pertinent questions in such a book as this. There is a certain danger in vulgarizing notions of medicine, strictly so called; but it can only be beneficial to make every one acquainted with the precepts of hy- giene, which cannot become popular until they have penetrated into the habits and routine of national life. There is much to be done before modern society is practically on a level with the achievements of science; many prejudices must be uprooted, and many PREFACE. vii false notions must be replaced by those which are sounder and more just. For this reason, we have endeavoured to make this work intelligible to all. It may be read with profit by those who possess the elementary notions of natural science which are included in the course of. primary instruction. We therefore hope that the volume may find a place in the libraries of secondary instruction, and in public libraries. Although the work is not specially intended for physicians, yet practical men may not be indisposed to glance at it: it may, at any rate, serve as an intro- duction to the much more learned works of Cornil and Babés, of Duclaux, Klein, Koch, Sternberg, ete. We have given an important place to the botanical question, which is too often neglected in works on microbian pathology. From this point of view, the narrow bond which connects bacteria with ferments and moulds has to some extent marked out the plan we have adopted; namely, that of passing from the known to the unknown, from what is visible with the naked eye to that which is only visible with the aid of the microscope. Angers, September 10, 1885. TABLE OF CONTENTS. ei INTRODUOCTION. Mickoses AND PROTISTA ... wae ove ves see CHAPTER L Parasrrio Funet anp Movutps... vee oes oo I. General remarks on fungi one aes we II. Basidiomycetes: uredinem, the rust of wheat and grasses III. Ascomycetes : ergot of rye; mould of leather and dried fruit IV. Oomycetes, mucorinex, or moulds, strictly so called ; pero- nospore; potato-fungus wa wee V. Parasitic fungi of the vine: siiltnm, siitidew? ete. aes VI. Habitat and station of parasitic fungi: their destructive action See se VII. Parasitic fungi of invests, ‘conaiflered as auxiliaries a: man VIII. Muscardin, or disease of silkworms ... as IX. Parasitic fungi of the skin and mucous membrane of man and other animals... ose eee ves CHAPTER II. FermMents AND ARTIFICIAL FERMENTATIONS tes aes I. Definition of fermentation... o Per wee TI. Vegetable nature of ferments, or yeasta ses Sas oes TEL. Ferments of wine; alcoholic fermentation ... wee IV. Beer-yeast ... ties vee eee V. Concerning some other fermented drinks _ aus VI. Yeast of bread ooo eo one wis we PAGE CONTENTS. CHAPTER III. MICROBES, STRICTLY 80 CALLED, OR BAOTERIA I. The vegetable nature of microbes II. Classification of microbes, or bacteria ... fr III. The microbe of vinegar, and acetic fermentation IV. The microbes which produce the diseases of wine V. The microbe of lactic fermentation ave VI. The ammoniacal fermentation of urine VII. Butyric fermentation of butter, cheese, and ait VIIL. Putrid fermentation, game-flavour 1X. Aérobic and anaérobic microbes ... sia tee X. The microbes of sulphurous waters... eo XI. The microbes which produce saltpetre wee XII. The microbes which destroy building materials XIII. The microbes of chalk and coal ... ee cas XIV. Chromogenic microbes ee wee ay XV. The microbe of baldness a vos CHAPTER IV. Taz Miorosts or tHE Diszases or Dumestic ANIMALS I. Anthrax, or splenic fever II. Vaccination for anthrax III. Fowl cholera ... xe IV. Swine fever wa Re V. Some other diseases peculiar éy domeatic sivimate VI. Rabies was su VII. Glanders a VIII. Pebrine and flacherie, igo dicsases of ditkewornn CHAPTER V. Tux Micropes or Human Diseases eee _I. Microbes of the air, the soil, and water I. Microbes of the mouth and ascaies canal in a health y man Til. The aiilant iniershe of a salivs IV. The microbes of dental caries ie V. The microbes of intermittent or marsh fevers VL The microbes of recurrent fever and yellow fever VII. Typhoid fever and typhus VIII. ‘The microbe of cholera IX. Eruptive fevers : X. The microbes of croup and whooping-cough XI. The microbes of phthisis and ee XII. The microbe of pneumonia ... - XIII. Some other diseases due to cdciobea. XIV. The microbe of erysipelas XV. The microbes of pus, septicemia, etc. CONTENTS. one one XVI. The microbes of other diseases, due to wounds XVII. The mode of action of pathogenic microbes: ptomaines CHAPTER VI. PROTECTION AGAINST MicroBEs I, Antiseptic treatment of wounds: ment; Lister’s dressing ... II. Hygiene of drinking - water: Chamberland filter wee CHAPTER VII. scarlatina, small-pox, ineaslee. ete. Guérin’s protective treat- water free from microbes; LaxsoratTory RESEARCH, AND CULTURE oF MIoroBES CoNCLUSION ... aoe CHAPTER VIII. PoLymorpPaism or Mioroses CHAPTER IX. The Microbian Theory compared with nie Theories set forth to explain the Origin of Contagious Discases APPENDIX. A. Terminology of Microbes B. Micrococcus of phosphorescence C. Diseases of plants caused by bacteria D. Ptomaine of the microbe of fowl cholera E. Cesspools. G. Useful microbes H. Ptomaines of fish INDEX eee System of conveying everything to the sewers F., Sewers of Paris and the Plain of Gennevilliers gee woe 258 272 285 285 301 304 305 306 306 307 308 308 309 MICROBES, FERMENTS, AND MOULDS. INTRODUCTION. MICROBES AND PROTISTA. Micropes are the most minute living things which the microscope permits us to see distinctly, so as to study their organization. They are for the most part invisible to the naked eye, and even by the aid of a simple lens. In order to form an exact idea of their forms and structure, we require the strongest magni- fiers of modern instruments, which enlarge the object 500, 1000, and even 1500 diameters. The word microbe has been recently introduced into the French language; it did not exist eight years ago, and for this reason it will be sought for in vain in most dictionaries. It was under the following cir- cumstances that this term, now in such general use, was invented by Sédillot, an eminent surgeon, whose recent death is deplored by France. Those naturalists who have studied the most 2 MICROBES, FERMENTS, AND MOULDS. minute living things have at all times been at a loss to decide whether they have had to do with animals or plants. There can be no such doubt when we com- pare a tree of which the roots are fastened in the soil with a quadruped which moves freely on its surface. But these are highly developed forms, the one in the vegetable, the other in the animal kingdom. The lower representatives of the two kingdoms are, on the other hand, often so much alike as to baffle the most experienced naturalist. The animals which are assigned to the order of Zoophyta, or animal-plants, have, as the name indicates, a form which led them to be for a long while regarded as plants ; many of them are fastened to the bottom of the sea or to rocks as if by actual roots, and, when superficially examined, their movements do not differ much from those which may be produced in true plants, as, for instance, in the mimosa. Many of the lower plants, belonging to the groups of Alge and Fungi, live in the water without being fixed by roots; many are animated by more or less apparent motion, at any rate during part of their existence, so that it is often somewhat difficult to dis- tinguish them under the microscope from those beings which are generally called Infusoria, and which are true animals. Hence it follows that the boundary between the animal and vegetable kingdoms remains indefinite, and that many of those microscopic organisms which MICROBES AND PROTISTA. 3 we have now to consider, may be assigned indifferently to one or the other kingdom. 1 Bory de Saint-Vincent, a naturalist belonging to the early part of the century, and after him Heckel, have attempted to evade this difficulty by creating between the animal and vegetable kingdoms an inter- mediate kingdom, which they have named Protista, indicating thereby that it includes the first animals which in the geological ages appeared on the earth’s surface. This kingdom: of Protista includes the fol- lowing groups, starting from the simplest and going on to those which are more complex :— *1. Monera (or Microbes, strictly so called; Schizomycetes, Bac- teria, Vibriones, etc.). . Amorphous Rhizopoda (or Amcebze). . Gregarinide. . Flagellata. . Catallacta. . Infusoria. . Acineta. . Labyrinthule., . Diatomacer. *10. Myxomycetes. *J1, Fungi. 12. Thalamophora (Foraminifera or Rhizopoda with a calcareous skeleton). 13. Radiolaria (or Rbizopoda with a silicious skeleton). ODI HMor wD The groups marked with an asterisk are those which we propose to study in this work. For the most part, the organisms assigned to them resemble plants in their general characters. They are parasites which derive their nutriment from other living beings. For this reason, many of these organisms are the 4 MICROBES, FERMENTS, AND MOULDS. cause of the more or less serious diseases which affect animals or plants. Naturalists who regard these para- sites as animals have termed them Microzoaria (from two Greek words signifying small animals). Those who regard them as plants have called them Micro- phyta (small plants), and it is still disputed which term is the most applicable to them. In other words, it is still undecided whether they should be classed in the animal or vegetable kingdom. It was at the Paris Academy of the Sciences, on the 11th of March, 1878, that Sédillot took part in one of the probably interminable discussions between the advocates of the Microzoaria and those of the Micro- phyta, and he suggested, with the critical sense for which he was distinguished, the word microbe, to which it appeared to him that every one could give their assent. In fact, the word microbe, which only signifies a small living being, decides nothing as to the animal or vegetable nature of the beings in question.* It has been adopted by Pasteur, and approved by Littré, whose competence to decide on neologisms is generally admitted ; it has been in common use in France for the last four or five years, and may now be regarded as definitively adopted into the French language, This word has not yet been fully introduced into * Béchamp terms microbes microzyma, or small ferments, since the chemical reactions which result from their vital activity are goncrally fermentations. MICROBES AND PROTISTA. 5 the English and German languages. In order to in- dicate the organisms which produce diseases, they make use of the word Bacteria, which is only the name of one of the peculiar species assigned to this group, and the one with which we have been longest acquainted. In this case, the name is generalized and applied to an entire group. : The Italian authors who have been recently occu- pied with the study of microbes have on their part adopted the name Protista, proposed by Heckel, and of which the sense, although not the etymology, is almost the same as that of the word microbe. In reply to the question whether there is any real advantage in establishing an intermediate kingdom of Protista between the two organic kingdoms of animals and plants, we must answer in the negative. This third organic kingdom only serves to render the structure of our modern classification more com- plex; and it includes, as may be seen from the list given above, a collection of very heterogeneous groups, which it would be more simple to leave in one or the other kingdom. We should, in our opinion, approxi- mate more closely to Nature’s plan by only admitting. two great kingdoms: the organic kingdom, which includes plants and animals; and the inorganic king- dom of minerals, The organic kingdom should then be divided into two. sub-kingdoms, animals and plants, of which microbes or protista, or whatever else they may be called, should form the connecting 6 MICROBES, FERMENTS, AND MOULDS. link, and testify to the common origin of the two great organic kingdoms. However this may be, we shall make use of the word “microbe” as the general designation of all the minute organized beings which are found on the borderland between animals and plants. We shall presently show that in the majority of cases these beings may be regarded as true plants, and this is at present generally admitted by most naturalists. Part played by Microbes in Nature.—The part played by microbes in nature is an important one. We find them everywhere ; every species of plant has its special parasites, and this is also the case with our cultivated plants—with the vine, for example, which is attacked by more than a hundred different kinds. These microscopic fungi have their use in the general economy of nature; they are nourished at the expense of organic substances when in a state of putrefac- tion, and reduce their complex constituents into those which are simpler—into the soluble mineral substances which return to the soil from which the plants are derived, and thus serve afresh for the nourishment of similar plants. In this way they clear the surface of the earth from dead bodies and faecal matter; from all the dead and useless substances which are the refuse of life, and thus they unite animals and plants in an endless chain. All our fermented liquors, wine, beer, vinegar, etc, are artificially produced by the species of microbes called ferments; they also cause bread MICROBES AND PROTISTA. 7 to rise, and from this point of view they are pro- fitable in industry and commerce. But in addition to these useful microbes, there are others which are injurious to us, while they fulfil the physiological destiny marked out for them by nature. Such are the microbes which produce dis- eases in wine; most of the changes in alimentary and industrial substances ; and, finally, a large number of the diseases to which men and domestic animals are subject. The germs of these diseases, which are only the spores or seeds of these microbes, float in the air we breathe and in the water we drink, and thus penetrate into the interior of our bodies, Hence we see the importance of becoming acquainted with these microbes. Their study concerns the agri- culturist, the manufacturer, the physician, the pro- fessor of hygiene, and, indeed, we may say that it concerns all, whatever our profession ‘or social position may be, since there is not a single day, nor a single instant, of our lives in which we cannot be said to come in contact with microbes. They are, in fact, the invisible agents of life and death, and this will appear more plainly from the special study we are about to make of the more important among them. Since it is easier to know and observe beings which are visible to the naked eye, we shall first speak of fungi—that is, of the larger microbes, with whose habits and organization we are also best acquainted. 8 MICROBES, FERMENTS, AND MOULDS. We will then go on to the study of the more minute ferments; and finally to that of bacteria (Schizophyta or Schizomycetes), which are, strictly speaking, mi- crobes, and which only become visible with the aid of the microscope. CHAPTER L PARASITIC FUNGI AND MOULDS. I. GENERAL REMARKS ON FUNGI. Every one is acquainted with the field and forced mushrooms, two varieties of one and the same species, wild or cultivated, and often seen at table. It is less generally known that the trufile is also a fungus; and that the large class of fungi includes moulds and many parasites which are more or less microscopic, which live at the expense of wild and cultivated plants, and attack animals and also the human subject. Fungi are among the lower plants, and differ from higher orders in their mode of life. It is well known that the large majority of plants are not nourished only by absorbing the mineral salts which, in a state of solution, their roots derive from the soil, but also, and chiefly, by decomposing the carbonic acid of the air, assimilating the carbon which, as cellulose, enters into the composition of all their tissues, and giving forth pure oxygen to the air. 2 10 MICROBES, FERMENTS, AND MOULDS. This function is not, as it was formerly erroneously supposed, a respiration in the inverse form from that of animals, All plants without exception breathe like animals by absorbing oxygen. The assimilation of carbon is a true nutrition, and as the decomposition of the carbonic acid gas which results from this assi- milation sets free a much larger quantity of oxygen than the plant requires for itself, it was for a long while believed that plants really breathed the car- bonic acid gas of the air, in the inverse method to that of animals. Fig. 1.—Agaricas in different as of development: 2, 3, a vertical section showing the formation of the head. The hyphe of the mycelium are shown in the lower part of the figure. The assimilation of carbon is effected by the leaves and green parts of plants; the green, granular sub- stance termed chlorophyll, which solely gives them this colour, as may be shown by the microscope, and which alone subserves this function of nutrition. Fungi, however, have no leaves nor other green parts; that is, they have no chlorophyl. They derive the cellulose which they contain, as well as all the sub- stances by which they are nourished, either from PARASITIC FUNGI AND MOULDS. 11 other plants, or from animals and from the organic substances which are decomposing in the soil, such ‘as dung and dead _ bodies. So that it may be said of fungi, that they subsist like animals by devouring plants or other animals; not like higher plants, which derive their nutriment from the soil or the air, and owe nothing to other living beings. . It is for this reason that some naturalists have regarded fungi as animals, and have classed them in the animal kingdom. We have seen that Heckel and the naturalists of his school have assigned them to the kingdom of Protista. But setting aside their mode of nutrition, which is likewise found in plants of a higher organization, such as the Orobranchee and some of the Orchidacee, fungi really exhibit all the characters of plants, and as such we shall here con- sider them, although they are plants of a peculiar and very low type. The class of fungi may be defined by saying that they are plants devoid of stems, leaves, and roots ; that they consist only of cells in juxtaposition, devoid of chlorophyl. They never bear a true flower, and are simply reproduced by means of very minute bodies, generally formed of a single cell, which is called a spore, and which represents the seed. In fungi of the highest type, such as that commonly known as the edible mushroom, the part which we eat and call the umbrella represents the flower or floral peduncle of other plants, and is in reality only 12 MICROBES, FERMENTS, AND MOULDS, the support or covering of the spores, which are fixed on the radiating lamelle that may be seen on in- verting the umbrella (Figs. 2 and 3). This umbrella or floral peduncle is the only part of the plant which appears above the soil, or the organic substances on which the fungus grows. But the really essential part of the plant is that Wig. 2.—Section of one ofthelamella § Fig. 3.—Spores of the Aymenium, greatly of the umbrella of Agaricus e: magnified, and resting on their supports a, b, spores of the hymenium or basides, a. (slightly magnified). : which does not appear on the surface; namely, the white filaments or hyphe which creep along the soil, the manure, or whatever supplies the nutritive matter, and which represent at once the root, the stem, and the . branches of the plant; this part is termed the myceliwm. We shall presently see that many of the lower fungi are without the organ we have called the umbrella, and which botanists term the hymenium or organ of repro- duction, and consequently consist only of mycelium. PARASITIC FUNGI AND MOULDS. 13 In this case, the spores or seeds are developed in the cells of the mycelium itself. This latter mode of reproduction also occurs in the higher fungi, which therefore possess two modes of reproduction and two kinds of spores: exogenous spores, which are externally developed, as we see on the hymenium (Fig. 2); and endogenous or internal spores, which are developed in the mycelium (Fig. 4). These spores not only differ in the site of their origin, but also in their form, size, structure, and in the end they fulfil in the reproduction of the fungus. There are in many cases several forms of exogenous spores. i ce Classification of F Ungt.— he ce es Agaricus The nature of the spores, and the very varied mode of reproduction, have led to the classification of fungi in a certain number of groups, of which we need only cite the most im- portant, and those which chiefly concern our present point of view. Such are— 1. The Hymenomycetes. 2. The Basidiomycetes. 3. The Ascomycetes. 4. The Oomycetes. Each of these groups is subdivided into several sections or families. Ferments and Schizomycetes, or . 14 MICROBES, FERMENTS, AND MOULDS. microbes, properly so called, are still often assigned to the class of fungi. We shall speak of them separately, and give our reasons for distinguishing them from true fungi. Hymenomycetes are the fungi which possess the hymenium or umbrella; all the edible species are included in this class, together with a great number of extremely poisonous species. They are generally of considerable size, and only a few among them are true parasites; they do not, therefore, enter into the plan of this work, and, in spite of the interest they present, we shall content ourselves with the brief notice of them we have just given. The other groups must, however, detain us longer. II. THE BAsIpIOMYCETES: UREDINEH, THE RUST OF WHEAT AND GRASSES. The name of cereal rust is given to a parasitic affection caused by a minute microscopic fungus which is developed on the leaves of wild and cultivated grasses. This rust appears in the form of orange patches, which gradually spread over the blades of wheat and other grasses, and its common name is due to this colour. Many of the plants belonging to other families are attacked by analogous parasites, and these fungi are all assigned by naturalists to the genus Uredo, and to the family of the Basidio- mycetes or Uredinew. PARASITIC FUNGI AND MOULDS. 15 Basidiomycetes have no endogenous spores, but they may have as many as four forms of exogenous spores. This is the case with the rust of wheat, termed by naturalists Uredo or Puccinia graminis, which appears in the spring on the blades of this plant. The patches of rust are covered with a fine dust, which, under the microscope, is seen to consist of small elongated bodies of a reddish brown, resting on a filament; these are the first spores of the fungus, and are termed uredospores (Fig. 5). If they are scattered over a blade of wheat which was previously healthy, they germinate by means of a hypha of mycelium, which penetrates the leaf and develops a fresh patch of rust. In harvest- time the patches are of a darker, almost black shade, owing to the development of a second kind of “$.cnnat tine ect from a blade of wheat, and spore. These are pear-shaped, displaying several uredo- os £ . * Spores and one teleutospore divided in two, with an enveloping —_ much magnified). membrane of considerable thickness; they are called teleutospores (Fig. 5). Teleutospores cannot germinate on a healthy blade of wheat, and consequently do not communicate rust. They may remain through the winter on thatch or wheat straw, awaiting the ensuing spring, and even then they cannot be developed upon a blade 16 MICROBES, FERMENTS, AND MOULDS. of wheat, but only upon the leaves of another plant, the barberry. Borne by the dew or by a drop of rain on to the young leaves of the barberry, the teleutospores germi- nate, and form reddish-brown patches which’ affect both sides of the leaf. On its lower surface the spores are smaller, and are termed spermata; their function is not thoroughly understood. The larger spores on the upper surface are called acidiospores (Fig. 6), and with these we are more concerned, since Fig. 6-—Section of a barberry-leaf bearing two cecidiospores, more or less developed, of Puccinia graminis (much magnified), they are destined to return to the wheat, rye, or other grasses, in order to reproduce the original rust. When they are placed on a blade of one or other of these grasses, the cecidiospores germinate at once, and it is soon covered with patches resembling those of the preceding year; when these patches are numerous, they dry up the blade and destroy the ear. Hay and straw affected by rust should never be given to animals as food, since such food may produce disease. Thus it appears that Puccinia graminis presents the phenomenon of alternation of generations; that is, PARASITIC FUNGI AND MOULDS. 17 the complete development of the fungus is only effected by its transference from one plant to another. This phenomenon may be frequently observed in animal and vegetable parasites, and it seems to be designed in order to secure the preservation of the parasitic species, by permitting it to grow on two plants in succession, of which the development occurs at different periods of the year; such is the case with the barberry, which is developed in early spring, while wheat is developed in summer. For a long while it was believed that Gcidiwm berberidis, Uredo linearis, and Puccinia graminis were so many distinct species; but it is now known, as we have stated, that they are only three successive phases of the development of a single species.* Other Uredinee, constituting the modern varieties of Ustilago and Tilletia, are more apt to affect the ears of wheat and other grasses. This disease is termed by agriculturists smut or caries (Uredo carbo or Ustilago segetum, and Tilletia caries). The diseased grain merely appears to be of a somewhat darker colour, but on pressing it between the fingers, there issues from it a blackish, oily pulp, which smells like rotten fish. Bread made from the flour of such corn has an acrid and bitter taste, and although it does not appear to be directly injurious to health, * So, again, Ecidium rhamni (Nerprun or Bourdaine) produce Uredo rubigo-vera and Puccinia coronata of wheat and cats. (See Fig. 7.) 18 MICROBES, FERMENTS, AND MOULDS. it cannot be regarded as fit for food. The dust arising from these fungi often produces in threshers in a barn an irritating cough, which ceases when they are no longer subject to the exciting cause. The verdet, or, as the Italians call it, verderame of maize is due to the presence of the same parasite (Ustilago segetum,Uredo carbo, or Sporisorium maidis) on the grains of maize, and for a long while it was believed to produce pellagra, a common disease among the peasants who live on maize. It is now known that pellagra is due to the growth of another fungus, much resembling the ergot of rye, of which we shall speak presently. Other species of Uredinee attack sorghum, rice, etc., and, indeed, very many plants are affected by parasitic fungi belonging to the genus Puccinia ee rey and to allied genera, and it is probable Uredo rubigo ver that they almost all present the phe- am ‘nomenon-of alternation of generations. A simple means of freeing our fields from the rust of wheat is indicated by what we now know of the alternation of generations which ensures the propaga- tion of this fungus. We must destroy all the barberry bushes which are found in the vicinity of cornfields, Popular opinion, although ignorant of the phenomenon of alternation of generations, has long regarded the neighbourhood of the barberry as the principal cause of the rust of cereals. PARASITIC FUNGI AND MOULDS. 19 In 1869, De Taste ascertained that in the parish of Chambray, after the peasants had uprooted all the barberries which grew in the hedges, the harvest, which had been bad in the foregoing year, was gathered in under normal conditions for three suc- cessive years. After the Lyons Railway Company had planted a barberry hedge to fence the railway in the parish of Genlis (Céte-d’Or), the cornfields bordering on the line were attacked by rust in an aggravated form. An inquiry made by the company showed that the disease was due to the barberry, and that where that plant was not found, the wheat was not affected by rust. On the other hand, a single shrub of barberry caused the disease to appear in a field in which it had never occurred before. The smut of wheat may be destroyed by the application of quicklime, either dry or dissolved in water, which destroys the fungus or checks its develop- ment. Seed corn should always be subjected to this operation when affected by smut, In default of quick- lime, sulphate of copper is sometimes used, which may be injurious, or sulphate of soda, dissolved in water (eight kilograms to the hectolitre). This should be done the day before the seed is sown. In the case of corn intended for food, another process called pedle- tage must be employed; this consists in the frequent stirring of the granaried corn, either with the hand or with Vallery’s movable granary floor, so as to dry and aérate it, and expel the dust and damp, which are favourable to the development of fungi. 20 MICROBES, FERMENTS, AND MOULDS. TI. Ascomycetes ; Ercot or Rye; Tae MovuLD oF LEATHER AND DRIED FRUITS. In distinction from the species just described, the fungi in this group possess endogenous spores, enclosed in a sac or special envelope which is called an ascus ; hence the name of the family. Truffles, or Tuberacee, are only reproduced by the spores contained in these asci; but most of the other ascomycetes present in addition several forms of spores, and the phenomenon of alternation of generations has led to the belief that in this case, as in that of the foregoing group, many of the so-called species are only successive transformations of one and the same species. This is the case with the ergot of rye, a product used in medicine; it is, however, a serious and dangerous disease of several of our cereals, and particularly of rye (Fig. 8). Ergot is caused by a minute parasitic fungus which attacks the ear of rye when it is in flower. The young flower is covered with a white mass, consisting of microscopic spores, formerly termed sphaceliwm (Fig. 9). These spores reproduce themselves on other flowers, and propagate the evil. The mycelium formed by the germination of the sphacelium affects the grain, forms in it a thick felt- work, and is developed so as to constitute the elongated _ substance termed sclerotis (on account of its hardness), or ergot; it is called at this stage Claviceps purpurea. PARASITIC FUNGI AND MOULDS. 21 The sphacelium surrounding it falls off, and until the Fig. 9.—Sphacelium or Claviceps purpurea, the first stage of ergot (magnified). Fig. 8.—Ear of rye, on Fig 10.—Ergot bearing the organs which there are several of fructification (magnified). grains of ergot. following spring the ergot remains stationary on the soil on which it has fallen. 22 MICROBES, FERMENTS, AND MOULDS. In the spring, owing to the heat and moisture, the hyphe of the scleroti Fig. 11.—One of the heads or organs of fructification in ergot, still more maghified. a, peritheces, s swell and, send forth numerous branches, bearing at their ex- tremity a sort of rounded head, in which the asci or peritheces are developed (Figs. 10, 11, 12); the endogenous spores issuing from these asci germinate on the rye-blossom, and produce there a fresh sphacelium, then a second ergot, thus always passing through the same cycle of alternation of generations. Most of the Graminacee and several Cyperacew are capable of producing ergots resembling those of rye, Fig. 12.—Portion of preceding figure under a very high magnifying power, showing at b the asci, and at c the spores issuing from the asci or peritheces. and possessing the same medical properties. The sug- gestion has been made that instead of the ergot of rye PARASITIC FUNGI AND MOULDS. 23. the ergot of wheat should be used in medicine; it is larger, harder, and more elongated in form, and it also appears to be less perishable. Ergot of rye, especially when powdered, strongly resembles meat in smell, and only becomes unpleasant when the powder is spoiled by being kept in a damp place; it then smells like rotten fish, and this is the case with many other fungi. At first the taste is not very apparent, but it after- wards produces on the pharynx a somewhat persistent sense of constriction. The chief action of this drug consists in producing contraction of unstriated muscu- lar fibres, especially those of the uterus. Ergotine and ergotinine are extracted from it, and these, which are its active principles, are often employed in thera- peutics in preference to raw ergot. In large doses ergot is a strong poison. It then produces characteristic symptoms, dilatation of the pupils, retardation of the circulation, vertigo, stupor, and even death. Bread made with flour from which the ergot has not been extracted may produce the grave symptoms known as ergotism, and these soon become fatal unless the use of such bread is discontinued. Sometimes nervous symptoms predominate, and this is termed convulsive ergotism ; sometimes the disease takes the form of gangrene of the extremities, or gangrenous ergotism, but these two forms are only two phases of one and the same disease, and often occur in the same 24 MICROBES, FERMENTS, AND MOULDS. individual. In countries where rye bread constitutes the chief food of the rural populations, as in Brabant, the north of France, Orléannais and Le Blaisois, fatal epidemics have been recorded at different times in the Middle Ages, under the name of St, Anthony’s fire. The first symptoms are a species of intoxication, sought after by the peasants, and becoming habitual, like alcoholic drunkenness, up to the moment when con- vulsions and gangrene set in, and death soon follows. Ergot of maize produces analogous phenomena. In countries where maize bread and cakes are in use, as in Italy and South America, it appears to be the cause of the disease improperly called Pelade. Of this the shedding of the hair and skin is the first symptom.* Fowls which feed on ergotized maize lay eggs which are devoid of shell, owing to their premature expulsion from the uterus; their combs become black, shrivel, and finally drop off; and they even shed their beaks. All these phenomena may be easily explained by the action of ergot on the muscular fibres of the uterus, and of the blood-vessels. Recent research has shown that Pelade is identical in its cause and external symptoms with the disease known in northern Italy and in the south of France as pellagra, and in Spain as the rose sickness. The latter * We shall presently see that the name Pelade was formerly given to another parasitic affection, peculiar to that part of the skin covered with hair. These two diseases must not be confounded, notwithstand- ing the similarity of name, since they are produced by two fungi belonging to different groups. PARASITIC FUNGI AND MOULDS. 25 name is due to the red stains which cover the skin, afterwards drying up and falling off in the form of seales. At first the general health is not affected, and several years may intervene before the occurrence of vertigo, a want of appetite, emaciation, and finally the torpor and convulsions which precede death. These ill effects may be prevented by baking the maize before grinding it, according to the process in use in Burgundy. There is another very common fungus also belong- ing to the group of ascomycetes, termed Lurotiwm repens. This mould appears upon leather which has been left in a damp place, and on vegetable or animal substances in process of decomposition or badly pre- served, and especially upon cooked fruits. This mould is of a sombre green, a colour by no means due to the presence of chlorophyl. On the mycelium, which spreads over the substance of the leather or of the fruit-skin, small stems are developed, consisting of a jointed tube, and terminating in an enlarged head on which chaplets of small grains are formed, each of which is a spore. This was formerly termed Aspergillus glaucus, and was regarded as a peculiar species (Fig. 13). When, however, this mould is developed in a place in which the supply of air is limited, small gold-coloured balls may often be observed beside or in the midst of the stems, and these are filled with asci, each containing eight spores. This second form has been termed Lwro- tiwm repens. It has recently been ascertained that 26 MICROBES, FERMENTS, AND MOULDS. the balls in question are produced from the same mycelium as Aspergillus glaucus, and that conse- quently the chaplet of stalks and the balls filled with asci are merely two organs of the same fungus. Fig. 13,—Aspergillus glaucus, mould on leather and rotten fruits : a, hypha bearing the chaplet of spores 6; c,a germinating spore; a, ball of Eurotium ; e¢, ascus enclosing the endogenous spores (magnified). The chaplet of spores in Aspergillus glaucus repre- sent the white exogenous spores, or the sphacelium of the ergot of rye, and those which are subsequently PARASITIC FUNGI AND MOULDS. 27 produced in the yellow balls correspond with those which issue from the asci developed on the sclerotis; these are endogenous spores. Many of the parasitic fungi belonging to the genera Erysiphe, Spheria, Sordaria, Penicillium, etc., pre- sent a similar mode of vegetation, and affect a large number of plants. Such is the Oidiwm of the vine (Erysiphe Tuckert) to which we shall presently revert. IV. Oomycetes, MucoRINE&, OR MOULDS, PROPERLY SO CALLED; PERONOSPOREE; THE PoTaTo-FuNGUS. In all the parasitic fungi of which we have hitherto spoken there is no sexual reproduction analogous to that of the higher plants; there are no male and female organs comparable to the stamens and pistil. This sexual reproduction exists in the oomycetes, although only in a very elementary form. In addition to the ordinary spores which we have noticed in other fungi, there are others termed oospores, which are formed by the fusion of the originally distinct contents of two different cells. In the family of the mucorinez, which includes most of the fungi commonly called moulds (Fig. 14), Gog's excrement (mag. the two cells of which the contents ™"*” are fused together are similar. In the peronosporex, however, which includes the potato-fungus, one of the 28 MICROBES, FERMENTS, AND MOULDS. cells is larger than the other, and persists alone up to the moment when the oospore is mature. It must, therefore, be regarded. as the female cell; while the Fig. 15.—Reproductive organs of Mucor mucedo (much magnified). other, which is smaller and soon withers away, is the male cell. The mycelium of the oomycetes is developed in a more or less liquid medium, like all other decomposing and putrefying substances. The ordinary spores are PARASITIC FUNGI AND MOULDS. 29 very small, and are formed within a small enlargement (sporangiwm) borne on a free hypha of the mycelium. Their succession is constant and numerous as long as the plant is in a favourable medium in which it can flourish. The spores which are found in the same medium germinate, and reproduce a mycelium similar to that from which they had their origin. Fig. 16.—Reproductive organs of Peronospora, calotheca (much magnified). The oospores may be as much as a thousand times larger in volume than ordinary spores. They are only formed when the growth of the fungus is on the wane, as, for instance, when the substance serving as a sup- port to the mycelium is drying off: a long period may elapse before they germinate (Figs. 15 and 16). 30 MICROBES, FERMENTS, AND MOULDS. Fig. 15 represents the reproductive organs of Mucor mucedo. 1 is the sporangium filled with ordinary spores; in 2, the wall of the sporangium has disappeared, so as to show the free spores round the central columella; 3 and 4 represent the germina- tion of these spores, giving forth their hyphe; 5 gives the conjugation of the sexual spores, which are fused into one large oospore, 6; of this we see the germina- tion in 7, and it produces a hypha terminating in a sporangium. Fig. 16 represents the same organs in a Perono- spora. In 1 we see the mycelium of the fungus penetrating the tissue of the infected plant; in 2, the fructifying apparatus containing the ordinary spores issues through a stoma, ramifies, and produces sporangia at the extremity of each branch; in 3 and 4 we see two spores which have issued from these sporangia germinating and penetrating the epidermis of a leaf through the stomata (a, b); in 5 we see the conjugation which has taken place between two dissimilar cells: the male cell, smaller in size (antheridvwm) is applied to the large female cells (oogonium), and after this mode of fertilization it is termed an oospore, which is represented in 6. Mucor mucedo, and other species of the same genus, form the small downy tufts of a greyish white colour which may be observed on mouldy bread, rotten fruits, and on the excrement of horses, dogs, and rabbits. When examined under the microscope, the PARASITIC FUNGI AND MOULDS. 31 filaments of which these tufts consist display at their extremities the sporangia represented in Fig. 15, 1. On rotten fruits, the spores of these fungi germinate in five or six hours by introducing their hyphze through the epidermis. Sleepiness, which is only the first stage of rottenness, is, according to Davaine, to be ascribed to the action of these fungi. Fruit in this mouldy condition is sometimes unwholesome. The potato-fungus, Peronospora infestans, is one of the most dreaded scourges of this valuable plant. It attacks the lower surface of the leaves and stalks, and appears in the month of July, in the form of brown patches. The long hyphez penetrate deeply beneath the epidermis, and will even propagate them- selves on the tubers. Among the causes which produce or promote this disease, agriculturists place the excessive moisture of the soil, setting the plants too late in the season, the use of bad seed, the premature and exhausting germination of the tubers before they are planted, and the use of fresh dung which is not sufficiently decomposed. The following process is indicated as likely to prevent the development of this parasite. In the spring, the first protective ridge should be prepared with a flat top, from eight to ten centimetres high, and from twenty-five to thirty centimetres wide. In the first fortnight of August, a second protective ridge should be earthed up, of which the edge should 32 MICROBES, FERMENTS, AND MOULDS. be acutely sloped, and the stalks of the plant should be turned down into the furrow, so that any spores which may be on the leaves may be washed off them by the rain, and not come into contact with the stem and roots of the plant. It is probable that earth-worms diffuse the spores of this fungus, as well of those of many other microbes. According to Prillieux, beetroot is attacked by another species of Peronospora, which causes the leaves of the plant to wither and fall. The remedy consists in burning the dead leaves on which the oospores remain during the winter, or, at any rate, in not allowing them to be placed on the dung-heap. The mildew which affects the vine is also a species of Peronospora (P. viticola) as we are about to show. V. Parasitic FuNGI oF THE VINE: O{DIUM, MILDEW, ETC. The parasites of the vine are so numerous as to require a separate chapter. Some years ago, in 1870, fifty of them were enumerated by Roumegutre, a well- known specialist, and the number is now more than doubled. We shall only now speak of the more important, of those which are especially injurious to the vine, and which consequently are the most interesting to us, PARASITIC FUNGI AND MOULDS. 33 Oidium. — Oidium, or LHrysiphe Tuckeri — so called from the name of the vine-grower by whom it was first described—has been longest known to us among these parasitic fungi. It belongs to the group of Ascomycetes, and appears to have reached us from America in 1845, in which year it was first observed in England. Thence it passed over to France. In 1847 it was noticed in the neighbourhood of Paris; and afterwards, in 1850-1851, in the south of France, where for twenty-five or thirty years it raged with such intensity as to threaten for some years the almost complete destruction of the vine- yards, a destruction which is now taking place under the attacks of another parasite, belonging in this instance to the animal kingdom: Phylloxera vastatrix. The oidium, the white disease or mewnier, was equally destructive in the vineyards of Madeira, so that it was necessary to uproot all the vines, and replace them by sound plants which were incapable of bearing grapes for some years. The oidium appears on the grape in the form of greyish filaments, terminating in an enlarged head, which contains an agglomeration of spores, not free or in a chaplet, as in Aspergillus (Fig. 18). These spores escape as fine dust, diffuse themselves in the air,and spread the disease afar with extreme facility. If a spore lodges on a vine-leaf under favourable conditions of moisture and warmth, it soon germinates, penetrates the epidermis by means of its hyphe, and 3 34 MICROBES, FERMENTS, AND MOULDS. forms floury patches which send forth a peculiar musty smell. The oidium may remain latent on the vine-stock throughout the winter. In the spring it reappears in yellowish patches on the earliest leaves, on which it is rapidly propagated; the plant languishes, and the leaves become palevand, as it were, anzemic. Very dry weather is unfavourable to oidium, and so also are heavy rains, which wash the fruit and leaves, and carry away the spores on to the soil. The remedy consists in the application of sulphur to the infected vines. Flowers of sulphur is used, which acts upon the fungus by gradually setting free sulphurous acid. Under this influence the microscope shows that the superficial mycelium and the fragile spores dry up as if they were burnt (Ed. André). Three successive applications are necessary, and these are made with the help of a special instrument in the form of a pair of bellows, to which a rose is affixed, in order to disseminate the flowers of sulphur. The first application is made in spring, when the shoots are from eight to ten centimetres long; the second directly after the vine has blossomed; and the third when the grapes begin to ripen. The opera- tion in spring is the most important, and should be performed with the utmost care, so as to affect all the hybernating spores from which the succeeding generations would issue. Not only the upper and lower sides of the leaves must be dusted, but also PARASITIC FUNGI AND MOULDS. 35 the branches and the stock itself, The third applica- tion should be made early enough for the sulphur to have disappeared from the grapes before the vintage takes place, It is evident that its introduction into the wine would have the worst effect: in process of fermentation sulphuretted hydrogen would be given off, which is injurious to the alcohol, and this gas would give an unpleasant taste to the wine. The morning is the best time for applying the sulphur, since the dew enables the powder to stick to the leaves and branches; and it should be made on a fine day, since heavy rain would carry off the sulphur before it has time to act upon the oidium. The sulphur which ultimately reaches the soil below the vine is transformed into sulphate of lime, which is an excellent dressing for the vine. Mildew.—This new parasite, of which the scientific name is Peronospora viticola, belongs to the group of Oomycetes. It also comes to us from America. It was imported into Europe in 1878, with the American plants destined to replace those destroyed by the phylloxera, and was rapidly diffused through France, and thence to Algeria. It appears in the form of irregular patches of a whitish colour, not very thick, and with an almost crystalline appear- ance like that of a saline efflorescence (Planchon). It has not the mouldy smell of oidium, and appears later in the season, generally on the autumn shoots. Its mycelium penetrates more deeply than that of 36 MICROBES, FERMENTS, AND MOULDS. oidium. Brown patches appear on the upper surface of the leaf, as if it had been scorched; and in corre- spondence with these there is a delicate down “like the whiteness of a slight hoar-frost” (Vaissier) on its lower surface. The hyphe issuing from the mycelium ramify at right angles, and these branches bear the spores, as in the potato-fungus, Peronospora infestans (Figs. 17,18). These numerous spores, diffused through the air, are powerful sources of contagion. Fig. 17.—Mildew: a, vertical section of a leaf, bearing tufts of Peronospo a viticola on its lower surface; b, a withered leaf, bearing the winter spores (oospo:es) (x 20 diam.). This parasite destroys the tissue of the leaf, exhausts it, and finally causes it to wither and fall. Those which are least affected have only diseased patches. The bunch of grapes and the young herbaceous shoots are rarely affected. In addition to the ordinary or summer spores of which we have spoken, the sexual spores must be noted ; the oospores; or dormant winter spores, which PARASITIC FUNGI AND MOULDS. 37 hybernate in the tissue of the leaf itself (Fig. 17, b), and germinate in the spring. The conjugation of the sexual spores, as well as the ripening of the summer spores, and the germination of the zoospores which issue from them, can only occur in a drop of water, rain, dew, or mist, so that a persistent drought checks the propagation of this fungus. The parasite injures the stock by stripping it of its leaves, thus hindering the nu- trition of the plant; moreover, the grapes, since they are im- perfectly protected from the sun, dry up before they are Fig. Fiietartis of tufts of Pero- ripe. Sometimes, also, the — Bgore inekans isauing vom fungus attacks the grape itself, spore(x dee or its peduncle, Vines planted in a moist soil resist its attacks better than others, simply because the nature of the soil makes the plant more vigorous, and suitable manure acts in the same way. When the fungus is developed, it may be destroyed by sulphur mixed “ with powdered lime. Since its mycelium is more deeply seated than that of oidium, it is necessary to have recourse to more vigorous measures in order to reach it. Powdered borax has also been pre- 38 MICROBES, FERMENTS, AND MOULDS. scribed, in the proportion of five grammes to a. litre of water; also a solution of sulphate of iron, one kilogram to two litres of water, with which the stock should be washed fifteen days before the shoots begin to start (Millardet). Mme. Ponsot, in Bordelais, has used, the same substance mixed with lime (four parts of powdered sulphate of iron to twenty parts of lime). The fallen leaves which contain the winter spores, or oospores, should be burnt or buried. The stocks should be irrigated as often as possible, and the leaves should be dusted with lime in order to dry off the dew or mist, which favours the fertili- zation of the oospores. Some species of vines resist the disease better than others, and this is the case with the Labernet, a vine from Médoc, which has remained almost entirely free from it in infected regions of Algeria. Anthracnosis, or Black-rot.—This fungus, of which the name is Phoma uvicola, or Sphaceloma ampeliwm, belongs to the ascomycetes. Of all the parasites of the vine it was the earliest known, but it was only in 1878 that its devastations were important enough to attract attention. Like the two preceding fungi, it is reproduced by spores carried afar by the slightest breeze. Heat and moisture are favourable to its pro- pagation, which is checked by drought. It appears on the young shoots in the month of May, in the form of.round black spots which gradually spread over the twigs, leaves, and grapes PARASITIO FUNGI AND MOULDS. 39 The young stalks assume a sickly appearance, and often wither off, together with the leaves and fruit. When the fungus fastens on the fibro-vascular bundles of the leaves before their complete develop- ment, the leaves shrivel and curl up, and perform their functions imperfectly ; when it attacks the petiole or peduncle of the bunch of grapes, it dries up, and the destruction of all the parts in dependence on it soon follow. It is this fungus which, under the name of rot, now devastates the American vineyards. Sulphur is by no means so efficacious in this case as it is with oidium, but the following treatment is prescribed by Portes :— 1. The prunings of the vine and other remains of the preceding years should be destroyed, 2. The suckers and young shoots should be dusted, in the second fortnight of April, with slaked lime which has been finely powdered, and this operation should be repeated once a fortnight up to the end of June. 3. Sulphur should be applied at the usual times, especially if there is any oidium. 4 The vines should be drained and irrigated as often as possible. 5. In all cases in which the fungus can be detected, powdered lime should be applied at the interval of some days, alternately with the same substance mixed with flowers of sulphur. Aubernage, called by the Italians the Black disease, must not be confounded with Anthracnosis. Accord- ing to recent researches, aubernage is not produced 40 MICROBES, FERMENTS, AND MOULDS. by a fungus, but by a degeneration which is either spontaneous or, as Pirotta and Cugini suggest, the work of bacteria, and which consists in the trans- formation of the cellulose and starch of the plant into dextrine, as Comes asserts, or, according to Pirotta, into tannin. This disease appears in three stages: (1) a simple discolouration of the sap, which assumes a tawny black shade without checking vegetation; (2) a begin- ning of necrosis, which renders the plant unhealthy ; (8) a complete necrosis, which affects the woody parts and arrests the growth of the plant. This disease is contagious, which leads us to believe that if it is not produced by a fungus, it is at any rate due to the development of a bacterium— that is, of a microbe. The remedy indicated by Italian naturalists con- sists in the application of salts of potassium, which may be extracted at small cost from the ashes of the vine branches which are burnt upon the spot. Resleria hypogea, or Rot.—This parasitic fungus is found on the vine-roots, and has been recently studied by Prillieux. The vine affected by this parasite languishes for some years and then dies. The evil spreads by means of the roots to adjoining stocks, and the parts affected spread like the patches formed by the phylloxera. The roots rot away. This disease has been widely spread in Haute Marne. This small fungus is distinct from one which bears PARASITIC FUNGI AND MOULDS. 41 the same French name, Pourridié, which is found in the south of France, and has been studied by Planchon and Millardet. These naturalists describe it as formed by the rhizomorphous mycelium of a large hymenomycetous fungus, Agaricus melleus. Resleria is very different. It isa small white fun- gus, with a white or ash-coloured head, from eight to ten millimétres in size, of which the mycelium lives in the interior of the vine-roots, penetrating and profoundly affecting all the tissues of the roots, and producing in the autumn the fructification which comes to the surface. ; It is generally developed in marly and argillaceous soils, after a rainy season, and in the low-lying parts of vineyards on the slope of a hill. It thrives in the moisture which lies below the surface of the soil, and it is therefore important to improve the con- dition of those sub-soils which are impermeable. It is also necessary to separate the stocks, so as to prevent their roots from interlacing, and to uproot and burn diseased vines, since the fungus may subsist for several years in dead and dried roots. If, which is almost always the case, any fragments of roots remain in the ground, they will reinfect the sound stocks which have been substituted for them. Remarks on Diseases of the Vine—We may be surprised that this valuable plant, which has been so carefully cultivated in France, should be attacked by such a number of parasites, both animal and 42 MICROBES, FERMENTS, AND MOULDS. vegetable. Yet we should rather be surprised that the vine has not been completely destroyed by the combination of such diverse scourges, and that it has effectually resisted them in several regions of France. When we consider that for long years the same hoary old stocks have been required to produce grapes without truce or mercy, and often without taking pains to supply to them by a fitting manure the nourishment which is withdrawn from them by the fructification of the grape, we shall be less astonished at the decadence of our vineyards. And, indeed, enlightened minds ascribe the attacks of these numerous parasites to the weakness and exhaustion of our vines, rather than to any accidental cause, such as an importation from without. The principal remedy may, therefore, be found in restoring the strength of the vine by the planting of young suckers, and still more of seedlings. Instead of attempting to introduce foreign plants, which it may not be easy to acclimatize, and which will certainly be less valuable than the vines we have lost, it would surely be better to seek to regenerate our indigenous kinds by crossing the cultivated stocks with wild vines, or else, as Millardet suggests, by crossing them with each other. The attempt might also be made to graft the stocks from Bordeaux and Burgundy on wild or American vines, which offer a better resistance to the attacks of the phylloxera. PARASITIC FUNGI AND MOULDS. 43 VI. Hanirar or Parasitic FUNGI: THEIR DrEstTRUC- TIVE ACTION. The habitat of parasitic fungi is extremely varied. Roumegutre, in his Cryptogamie illustrée, has devoted more than forty pages of a large quarto, printed in three columns, merely to the enumeration of fungi, classified according to their position in plants, animals, organic or inorganic substances, and the author himseli admits that this list is far from complete. Parasitic fungi are found on plants belonging to all the families of the vegetable kingdom, and also on other fungi; on living animals, vertebrate and invertebrate; on their dead bodies and on excrement; in stagnant waters and in the sea, on piles and rocks. Others prefer marshes, turf-bogs, heathy ground (which may be marshy or dry), dunes, caves and holes, and even completely covered by the soil, as is the case with truffles. Others, again, erow upon stones, walls, and rocks; in the open air or in ruins; or, like Zorula conglutinata, and Himantia cellaria, in the darkest caves, where they form a species of feltwork, often several centimetres in thickness, of a blackish colour, ragged, and extremely light, which in the course of a few. years overspreads the walls of cellars. Other fungi inhabit our houses, attack our food, clothes, utensils of every kind; wall-papers and books, of which the paste offers a nutriment which they can 44 MICROBES, FERMENTS, AND MOULDS. easily assimilate; linen; and even our toilet sponges, notwithstanding that they are in daily use. They may even be found on the most powerful chemical substances, on pastilles of sulphur, arsenical solu- tions, ete. “ The general belief,’ writes Roumeguére, “regards fungi as the result of decomposition. This belief is due to an imperfect acquaintance with the nature of these plants. Fungi are not only found on fragments of wood and decayed vegetables, but sometimes even on bare pebbles, on glass, on window-panes, on the lenses of microscopes, and on other polished surfaces. It must be supposed that fungi are able to extract the elements of nutrition even in such positions. Coprins, which have a surprising power of develop- ment, grow on amputated limbs. Young has recorded the appearance of a great number of these fungi, still in an imperfectly developed state, below the mattress on which a man was lying whose leg had been ampu- tated. The bed was cleaned, and in nine or ten days the fungus reappeared in the same abundance as before. Targionni-Tozetti had previously observed a, similar growth on the apparatus which surrounded é fractured limb in St. George’s Hospital, Modena.” Berkeley states that immediately after the of any vegetable substance, an army of fu PARASITIC FUNGI AND MOULDS. 45 putrefaction and of these fungi. The hardest wood yields to the same agents, not indeed so quickly, yet much more rapidly than would be the case from the action of the constituents of the atmosphere alone. When a log of one of our finest trees is attacked by fungi, it soon becomes only a mass of rotten wood, of which the woody tissue has been traversed and destroyed by the mycelium. If the same log were * merely subjected to the action of the weather, it might endure for half a century before becoming completely rotten. Merulius destruens (or M. lacrymans) attacks beams and the other pieces of wood used in building, and rapidly destroys them. The administrators of the Canal du Midi, Toulouse, were compelled to replace the oak piles which protect the sides of the canal as it traverses the town, on account of the ravages of Dematiwm gigantewm, one of the higher orders of fungi in its early form. At the end of the last century, the same fungus destroyed, in the course of - two or three years, the Foudroyant, a sixty-gun vessel. In order to stop the development of these fungi in wood used for building, and especially in wood in- tended for ship-building, it is expedient, as soon as the trees are felled, to steep them in a metallic antiseptic solution—as, for instance, in sulphate of copper. An experiment made by Niageli, a celebrated 46 MICROBES, FERMENTS, AND MOULDS. a botanist in Munich, demonstrates the action of micro- scopic fungi. on organic substances, exclusive of any previous deterioration. “T enclosed,” he says, “several loaves in a tin case, which was carefully but not hermetically closed. When the case was opened at the end of eighteen months, the loaves were reduced to a small mass, consisting almost entirely of filaments of mould, in which I could detect no trace of the substance of bread. This mass was soft and moist, like a mud-pie. It emitted a strong odour of trimethylamin: no trace of starch remained. One hundred parts in weight of the original bread were transformed into sixty-four parts in their moist state, and seventeen parts after desiccation in the open air. The starch had been consumed in order to form carbonic acid and water.” Badham sums up in a few words the destructive effects of microscopic fungi. “Mucor mu- cedo,” he writes, “devours our pre- serves; Ascophora mucedo turns -our bread mouldy; Molinia is nourished at the expense of our fruits; Mucor herbarium destroys Fig. 19,—Chatonium char- the herbaria of botanists; and Sf a toa Chetonium chartatwm (Actino- spora) develops itself on paper, on the insides of books, and on their binding, when they come in contact with PARASITIC FUNGI AND MOULDS. 47 a damp wall (Fig. 19). When beer or sweetmeats turn sour, it is the work of a fungus.” VII. Parasitic Funct of INSECTS, REGARDED AS ALLIES oF Man. Many microscopic fungi attack insects, both living anddead. We have all seen the bodies of flies still sticking to the window- pane or curtain, and surrounded by a species of aureole formed by the growth of a fungus, Penicillium racemosum, gece or sometimes Sporendonema muscae or —egnia eran” Saprolegnia ferax, of the family of Oospores (Figs. 20, 21, 22). Cordiceps attacks certain caterpillars of the genera Cossus and Hepialus, when they are buried in the sand before their metamorphosis into chrysalides, and kills them by the development of its mycelium in their tissue. These caterpillars may often be found, bearing on their backs a fungus longer than them- \selves (Fig. 23), ' Spheria militaris, a parasite to Bombyx pityocarpa, the caterpillar found on pine-trees, represents one of the few fungi which may be regarded as beneficial to man, since it destroys multitudes of these cater- pillars, and thus neutralizes the ravages caused by their devouring the young shoots and pine needles. In the Antilles there is a wasp called the vegetable 48 MICROBES, FERMENTS, AND MOULDS. wasp, because it is attacked during its lifetime by a fungus which it carries about for some time, and _which finally causes its death: this is Torrubia spherocephala (Tulasne). Isaria sphinguwm, another Fig. 21.—Two filaments of Sapro- Fig. 22.—Oogonium of Saprolegnia legnia containing spores (greatly surrounded-by Antheridia (much magnified). magnified). species of the same genus, has been observed on the back of a butterfly, which was poised upon a leaf as if alive, and which was probably killed by- the development of the fungus. These and other facts, not to speak of the muscardine of silkworms, to which we shall return, PARASITIC FUNGI AND MOULDS. 49 have given rise to a surmise that if we could discover the parasitic fungus of the phylloxera, we might transform it into a powerful auxiliary of agriculture, since by its aid the parasitic insect which now ravages our vineyards might be destroyed. From this point of view Giard has observed several of these parasites of insects, which he ealls Entomo- phthorec, from the name of their prin- cipal genus, Entomophthora. Such is E. rimosa, which attacks grasshop- pers and the diptera of the genus Chironomus, enveloping them in a thick feltwork formed by the winter spores, Fig. 23—Butterny- and speedily killing them. In the Cordiceps. = same manner Isaria pulveracea attacks Pyrrhocoris apterus, an insect which is often injurious to our kitchen gardens. It has been asked whether Lntomophthora Plun- choni, the parasite of the aphis, might not also prey upon the phylloxera, but the experiments made in this direction have not hitherto been so successful as to allow us to count on this means of averting the scourge. With the same object, Hagen has suggested the use of beer-yeast, which seems to have a destruc- tive effect on insects, as it is developed in their tissues. 50 MICROBES, FERMENTS, AND MOULDS. VIII. MuscarpIne, THE DisEAsE oF SILKWORMS. Muscardine, which is caused by a true fungus, Botrytis bassiana, must not be confounded with other diseases which attack the silkworm, such, for instance, as pebrin, which, as Pasteur asserts, is caused by a bacterium, or, strictly speaking, a microbe, and, accord- ing to the recent researches of Balbiani, by Psoro- spermia. We shall presently revert to this disease. Botrytis bassiana is a true mould, belonging to the group of Oomycetes, and allied to the potato- fungus, Peronospora. It is propagated by spores, which, when falling on a silkworm, germinate and penetrate its body. A mycelium is then developed, which may take possession of the whole caterpillar without appearing externally. The germination is rapid in proportion to the age of the silkworm. When death has been caused by the develop- ment of the mycelium, hyphz appear through the animal’s skin; these soon bear white, chalky spores, which are readily detached and float in the air in im- palpable dust like smoke. The silkworms on which the dust falls do not appear to be diseased, and eat with avidity, but they die suddenly. It takes from 70 to 140 hours to develop the spores and spread the contagion. It is difficult to free the breeding- houses from all the silkworms which die in this manner; those which die after having crawled up to the heather to prepare for their transformation PARASITIC FUNGI AND MOULDS. 51 into chrysalides are only thrown away when they are found on removing the cocoons. The clouds of dust dispersed by the silkworms perpetuate the disease in the best-ordered factories. When the heather is thrown out of window, and the rooms are swept to get rid of the dust, the spores float in the air and are dispersed by the wind. Damp favours the development of the fungus, and the introduction of healthy silkworms into an infected breeding-house will not extirpate the disease. In order to attain this object, it is necessary to get rid of all the dead silkworms before the development of the spores, and to destroy their bodies by burning them with the heather, or with quicklime. The breeding- houses should then be completely emptied, and the compartments should be purified and disinfected in the ordinary way by fumigation with sulphur, and washed with chlorine water, before fresh silkworms are placed in them. IX. Parasitic FuNGI OF THE SKIN AND Mucous MEMBRANE OF MEN AND ANIMALS. The skin-diseases of man and animals which are termed tinea are caused by the presence of parasitic fungi, just as the itch is produced by the presence of animals belonging to the group Acarus. These diseases are rendered eminently contagious by the dissemination of the spores of these fungi, which will 52 MICROBES, FERMENTS, AND MOULDS. germinate wherever the conditions of heat and moisture are favourable, even on a healthy skin, or where it is only irritated by a simple scratch. Ringworm, 27h 82)\7 e& a @ °_ —@ Fig. 69.—Bacillus anthracis, produced in guinea-pig by inoculation: corpuscles of blood and bacilli. In order to prove that the disease is really caused by Bacillus anthracis, Pasteur inserted a very small drop of blood, taken from an animal which had ‘recently died of anthrax, in a glass flask which con- tained an infusion of yeast, neutralized by potassium and previously sterilized. In twenty-four hours the liquid, which had been clear, was seen to be full of very light flakes, produced by masses of bacilli, readily ANTHRAX, 135 discernible under the microscope. A drop from the first flask produced the same effect in a second, and from that to a third, and soon. By this means the organism was completely freed from all which was foreign to it in the original blood, since it is calculated that after from eight to ten of such processes, the drop of blood was diluted in a volume of liquid greater than the volume of the earth. Yet the tenth, twentieth, and even the fiftieth infusion would, when a drop was inserted under the skin of a sheep, procure its death by splenic fever, with the same symptoms as those produced by the original drop of blood. The bacillus is, therefore, the sole cause of the disease. These cultures have often since been repeated by numerous observers, so that the microbe has been studied in all its forms, and the extent of its poly- morphism has been ascertained. At the end of two days the bacterium, which, while still in the blood, is of a short, abrupt form, displays excessively long filaments, which are sometimes rolled up like a coil of string. In about a week many of the filaments contain refracting, somewhat elongated nuclei. These nuclei presently form chaplets, in consequence of the rupture of the cell-wall of the rod which gave birth to them ; others, again, float in the liquid in the form of isolated globules. These nuclei are the spores or germs of the microbes, which germinate when placed in the infusion, become elongated, and reproduce fresh bacilli. 186 MICROBES, FERMENTS, AND MOULDS. These spores:are much more tenacious of life than the microbes themselves. The latter perish in a tempe- rature of 60°, by desiccation, in a vacuum, in carbonic acid, alcohol, and compressed oxygen. The spores on the other hand, resist desiccation, so that they can float in the air in the form of dust. They also resist a temperature of from 90° to 95°, and the effects of a vacuum, of carbonic acid, of alcohol, and compressed oxygen. In 1873, Pasteur, aided by Chamberland and Roux, carried on some experiments on a farm near Chartres, in order to discover why this disease is so common in some districts, in which its spread cannot be ascribed to the bite of flies. Grass,on which the germs of bacteridia had been placed, was given to the sheep. A certain number of them died of splenic fever. The glands and tissues of the back of the throat were very much swelled, as if the inoculation had occurred in the upper part of the alimentary canal, and by means of slight wounds on the surface of the mucous membrane of the mouth. In order to verify the fact, the grass given to the sheep was mixed with thistles and bearded ears of wheat and barley, or other prickly matter, and in consequence the mortality was sensibly increased. In cases of spontaneous disease it was surmised that the germs which were artificially introduced into food in the course of these experiments, are found upon the grass, especially in the neighbourhood of ANTHRAX. 137 places in which infected animals had been buried. It was, in fact, ascertained that these germs existed above and around the infected carcases, and that they were absent at a certain distance from their burial- place. It is true that putrid fermentation destroys most of the bacteria, but before this occurs a certain number of microbes are dispersed by the gas dis- engaged from the carcase; these dry up and produce germs, which retain their vitality in the soil for a long while. The mechanism by means of which these germs are brought to the surface of the soil and on to the grass on which the sheep feed is at once simple and remarkable. Earth-worms prefer soils which are rich in humus or decomposing organic substance, and seek their food round the carcase. They swallow the earth containing the germs of which we have spoken, which they deposit on the surface of the soil, after it has traversed their intestinal canals, in the little heaps with which we are all acquainted. The germs do not lose their virulence in their passage through the worms’ intestines, and if the sheep swallow them together with the grass on which they browse, they may contract the disease. The turning-up of the soil by the spade or plough may produce the same effect. A certain warmth is necessary for the formation of germs; none are produced when it falls below 12°, and the carcases buried in winter are therefore less dangerous than those buried in the spring and sum- 1388 MICROBES, FERMENTS, AND MOULDS. mer. It is, in fact, in hot weather that the disease is most prevalent. Animals may, however, contract it even in their stalls from eating dry fodder on which germs of these bacteria remain. ‘Pasteur and his pupils performed an experiment in the Jura in 1879, which clearly shows that the presence of germs above the trenches in which car- cases have been buried is the principal cause of inoculation, Twenty oxen or cows had perished, and several of them were buried in trenches in a meadow where the presence of these germs was ascertained. Three of the graves were surrounded by a fence, within which four sheep were placed. Other sheep were folded within a few yards of the former, but in places where no infected animals had been buried. At the end of three days, three of the sheep folded above the graves had died of splenic fever, while those excluded from them continued to be healthy. This result speaks for itself. Malignant pustule, which is simply splenic fever, affects shepherds, butchers, and tanners, who handle the flesh and hide of tainted animals. Inoculation with the bacillus almost always occurs in consequence of a wound or scratch on the hands or face. In Ger- many, fatal cases of anthrax have been observed, in which the disease has been introduced through the mouth or lungs, as in the case of the sheep observed by Pasteur. The human subject appears, however, to be less apt to contract the disease than herbivora, ANTHRAX. 139 since the flesh of animals affected by splenic fever, and only killed when the microbe is fully developed in the blood, is often eaten in farmhouses. In this case the custom prevalent among French peasants of eating over-cooked meat constitutes the chief safeguard, since the bacteria and their germs are thus destroyed. II. VaccINATION FOR ANTHRAX. The rapidity with which anthrax is propagated by inoculation generally renders all kinds of treat- ment useless; if, however, the wound through which the microbe is introduced can be discovered, it should be cauterized at once. This method is often successful in man. The pustule is cauterized with red-hot iron, or with bichloride of mercury and thymic acid, two powerful antiseptics, certain to destroy the bacteridium. It is expedient, as an hygienic measure, to burn the tainted carcases, and if this is not done, they should be buried at a much greater depth than is usually the case. But the preservative means on which chief re- lianece is now placed is vaccination with the virus of anthrax. Pasteur has ascertained that when animals are inoculated with a liquid containing bac- teridia of which the virulence has been attenuated by culture carried as far as the tenth generation, or even further, their lives are preserved. They take 140 MICROBES, FERMENTS, AND MOULDS. the disease, but generally in a very mild form, and it is an important result of this treatment that they are henceforward safe from a fresh attack of the disease ; in a word, they are vaccinated against anthrax. In the cultures prepared with the view of attenu- ating the microbe, it is the action of the oxygen of the air which renders the bacteridium less virulent. It should be subjected to a temperature of from 42° to 43° in the case of Bacillus anthracis, to enable it to multiply, and at the same time to check the pro- duction of spores which might make the liquid too powerful. At the end of the week, the culture, which at first killed the whole of ten sheep, killed only four or five out of ten. In ten or twelve days it ceased to kill any; the disease was perfectly mild, as in the case of the human vaccinia, of which we shall speak presently. After the bacteridia have been attenuated, they can be cultivated in the lower temperature of from 80° to 35°, and only produce spores of the same attenuated strength as the filaments which form them (Chamberland). The vaccine thus obtained in Pasteur’s laboratory is now distributed throughout the world, and has already saved numerous flocks from almost certain destruction. Although this process has only been known for a few years, its results are such that the gain to agriculture already amounts to many thousands of pounds. Toussaint makes use of a slightly different mode ANTHRAX. 141 of preparing a vaccine virus, which is, however, analogous to that of Pasteur. He subjects the lymph of the blood of a diseased animal to a temperature of 50°, and thus transforms it into vaccine. Toussaint considers the high temperature to be the principal agent of attenuation, and ascribes little or no im- portance to the action of the oxygen in the air. Chamberland and Roux have recently made re- _ searches with the object of obtaining a similar vaccine by attenuating the primitive virus by means of antiseptic substances. They have ascertained that a solution of carbolic acid of one part in six hundred destroys the microbes of anthrax, while they can live and flourish in a solution of one part in nine hundred, but without producing spores, and their virulence is attenuated. When a nourishing broth is added to a solution of one in six hundred, the microbe can live and grow in it for months. Since the chief condition of attenuation consists in the absence of spores, this condition seems to be realized by the culture in a solution of carbolic acid, one in nine hundred, and it is probable that a fresh form of attenuated virus may thus be obtained. Diluted sulphuric acid gives analogous results. However this may be, the vaccine prepared by Pasteur’s process is the only one which has been largely used, and which has afforded certain results to cattle-breeders. Public experiments, performed before commis- 142 MICROBES, FERMENTS, AND MOULDS. sions composed of most competent men, have clearly shown the virtue of the protective action. In the summer of 1881, the initiation was taken by the Melun Society of Agriculture. Twenty-five sheep and eight cows or oxen were vaccinated at Pouilly-le-Fort, and then re-inoculated with blood from animals which had recently died of anthrax, together with twenty- five sheep and five cows which had not been previously vaccinated. None of the vaccinated animals suffered while the twenty-five test sheep died within forty- eight hours, and the five cows were so ill that the veterinary surgeons despaired of them for several days. This experiment was publicly repeated in Sep- tember, 1881, by Thuillier, Pasteur’s fellow-worker, whose death we have recently had to deplore, before the representatives of the Austro-Hungarian Government ; and again near Berlin, in 1882, before the representa- tives of the German Government, and always with the same success. Up to April, 1882, more than 130,000 sheep and 2000 oxen or cows had been vac- cinated ; and since that time the demand for vaccine -from Pasteur’s laboratory has reached him from every quarter. III. Fowt CHouera. The sickness of barn-door poultry, which is com- monly called cholera, is caused by the presence in the OTHER DISEASES OF DOMESTIC ANIMALS. 143 blood of a small micrococcus or bacterium in the form of the figure 8, differing, therefore, in form from Bacil- lus anthracis, but also an aérobie. It may be cultivated in chicken-broth, neutralized by potash, while it soon dies in the extract of -yeast, which is so well adapted to Bacillus anthracis. The microbe of this disease may also be attenuated by culture, and it may be done more easily than in the case of anthrax, since it is not necessary to raise the temperature, as the bacterium of fowl-cholera does ‘not produce spores under culture. Pasteur has there- fore been able to prepare an attenuated virus well adapted to protect fowls from further attacks of this disease. IV. Swine FEveEr. The disease affecting swine, which is called rouge, or swine fever, in the south of France, has been recently studied by Detmers in the United States, where it is also very prevalent, and by Pasteur in the department of Vaucluse. It is a kind of pnewmo- enteritis. These observers consider that the disease is caused by a very slender microbe, formed, like that of fowl- cholera, in the shape of the figure 8, but more minute. Others say that there is a bacillus which was observed by Klein as early as 1878 in swine attacked by this disease. In spite of the apparent contradiction, it is 144 MICROBES, FERMENTS, AND MOULDS. probable that we have only two forms of the same microbe, for the bacillus in Klein’s culture at first resembles Bacterium termo, in the form of an 8, before it is elongated into rods. Pasteur has succeeded in making cultures of microbes in the figure 8. He has-inoculated swine with the attenuated form, after which they have been Fig. 70.—Swine fever: section of a lymphatic gland, showing a blood-vessel filled with microbes (much enlarged: Klein). able to resist the disease, so there is reason to hope that in the near future this new vaccine, containing the attenuated microbe, may become the safeguard of our pig-sties. V. OF SOME OTHER DISEASES PECULIAR TO DOMESTIC ANIMALS, An epidemic which raged in Paris in 1881 was called the typhoid fever of horses, and was fatal to more than 1500 animals belonging to the General Om- nibus Company in that city. This disease is also pro- OTHER DISEASES OF DOMESTIC ANIMALS. 145 duced by a microbe, with which Pasteur was able to inoculate other animals (rabbits); for this purpose he made use of the serous discharge from the horses’ nostrils. The inoculated rabbits died with all the symptoms and lesions characteristic of the disease. The attenuation of this microbe by culture is difficult, since at the end of a certain time the action of the air kills it. Pasteur has, however, found an expedient by which to accomplish his purpose. When the culture is shown to be sterile in consequence of the death of the microbe, he takes as the mother culture of a fresh series of daily cultures the one which was made on the day preceding the death of the first mother culture. In this way he has obtained an attenuated virus with which to inoculate rabbits, and the same result might undoubtedly be obtained in the case of horses. " There are many other contagious diseases which affect domestic animals, and which are probably due to microbes, such as, for instance, the infectious pneumonia of horned cattle. This was probably the first disease in which the protective effects of inoculation were tried according to Wilhelm's method. This method consisted in making an incision under the animal’s tail with a scalpel dipped in the purulent mucus or blood taken from the lung of a beast which had died of pneumonia; sometimes the serous discharge from the swelling under the tail of an inoculated animal was used for others. Fever and loss of appetite ensued, lasting from eight 146 MICROBES, FERMENTS, AND MOULDS. to twenty-five days, but the animal was afterwards safe from further attacks of the disease. Cattle plague, or contagious typhus, is likewise ascribed to the presence of a microbe with which we are as yet imperfectly acquainted. Experimental septicemia is entitled to special men- tion, since it has too often been confounded with anthrax, and has been unskilfully produced with the intention of vaccinating animals in accordance with Pasteur’s process. This occurs when too long an interval (twenty-four hours) elapses after the death of \ 5 Ve? Fig. 71.—Sept:c vibrio, bacillus of malignant cedema (Koch): a, taken from spleen of guinea-pig; 6, trom a mouse’s lung. an animal, before taking from it the blood intended for vaccine cultures. After this date the blood no longer contains Bacillus anthracis, which is succeeded by another microbe termed Vibrio septicus, differing widely from the anthrax microbe in form, habit, and character (Fig. 71). Bacillus anthracis is straight and immobile, while the septic vibrio is sinuous, curled, and mobile. Moreover, it is anaérobic, and does not survive contact with the air, but it thrives in a vacuum or in carbonic acid. Since Bacillus anthracis is, on OTHER DISEASES OF DOMESTIC ANIMALS. 147 the other hand, an aérobie, it is clear that the two microbes cannot exist simultaneously in the blood or in the same culture liquid. The inoculation with this frésh microbe is no less fatal; its action is even more rapid than that of Bacillus anthracis, but the lesions are not the same; the spleen remains normal, while the liver is discoloured. The septic vibrio is only found in minute quantities in the blood, so that it has escaped the notice of many observers. It is, however, found in immense numbers in the muscles, in the serous fluid of the intestines, and of other organs. It is very common in the intestines, and is probably the beginning of putrefaction. VI. RABIES. Rabies is a canine disease which is communicated by a bite, and the inoculation of man and: other animals by the saliva. We are not yet precisely acquainted with the microbe which causes the disease, but Pasteur’s recent researches have thrown consider- able light on its life-history, which is still, however, too much involved in obscurity. It must first be observed that the hypothetical microbe of rabies, which no one has yet discovered, should not be confounded with the microbe of human saliva ; this is found in the mouths of healthy persons, and will be briefly discussed in the following chapter. 148 MICROBES, FERMENTS, AND MOULDS. The following conclusions are the result of Pasteur’s researches into the virus of rabies. This virus is found in the saliva of animals and men affected by rabies, associated with various microbes. Inoculation with the saliva may produce death in three forms: by the salivary microbe, by the excessive development of pus, and finally by rabies. The brain, and especially the medulla oblongata, of men and animals which have died of rabies, is always virulent until putrefaction has set in. So also is the spinal cord. The virus is, therefore, essentially localized in the nervous system. Rabies is rapidly and certainly developed by tre- phining the bones of the cranium, and then inocu- lating the surface of the brain with the blood or saliva of a rabid animal. In this way there is a suppression of the long incubation which ensues from simple inoculation of the blood by a bite or intra-venous injection onany part of the body. It is probable that in this case the spinal cord is the first to be affected by the virus introduced into the blood; it then fastens on its tissues and multiplies in them. Asa general rule, a first attack which has not proved fatal is no protection against afresh attack. In 1881, however, a dog which had displayed the first symptoms of the disease of which the other animals associated with him had died, not only recovered, but failed to take rabies by trephining, when re-inoculated in 1882. Pasteur is now in possession of four dogs which are OTHER DISEASES OF DOMESTIC ANIMALS. 149 absolutely secured from infection, whatever be the mode of inoculation, and the intensity of the virus. All the other test dogs which were inoculated at the same time died of rabies. In 1884, Pasteur found the means of attenuating the virus. For this purpose he has inoculated a morsel of the brain of a mad dog into a rabbit’s brain, and has passed the virus proceeding from the rabbit through the organism of a monkey, whence it becomes attenuated and a protective vaccine for dogs. This is the first step towards the extinction of this terrible disease. VII. GLANDERS. This, again, is a disease easily transmitted from horses to man. Glanders, or farcy, is caused by the presence of a bacterium, observed as early as 1868 by Christot and Kiener, and more recently studied at Berlin by Schiitz and Lofler. This microbe appears in the form of very fine rods (bacillus) in the lungs, liver, spleen, and nasal cavity. Babés and Havas found this bacillus in the human subject in 1881. Experimental cultures have been made simultaneously in France and Germany, and have given identical results. Bouchard, Capitan, and Charrin made their cultures in neutralized solutions of extract of meat, maintained at a temperature of 37°. By means of successive sowings, they have obtained the production of un- 150 MICROBES, FERMENTS, AND MOULDS. mixed microbes, presenting no trace of the original liquid, and this was done in vessels protected from air- germs. These cultures may be carried to the eighth generation. Asses and horses inoculated with liquid containing the microbes produced by this culture have died with the lesions characteristic of glanders (glanderous tubercles in the spleen, lungs, etc.). Cats and other animals which have been inoculated in the same way die with glanderous tubercles in the lymphatic glands and other organs. It follows from these experiments that the microbe which causes this disease is always reproduced in the different culture liquids with its characteristic form and dimensions ; that uni-ungulates can be inoculated with it, as well as man and other animals. In fact, this microbe is the essential cause of the disease. VIII. PeBRINE AND FLACHERIE, DISEASES AFFECTING SILKWORMS. We have already spoken of muscardine, a silk- worm’s disease produced by a microscopic fungus; two other diseases are caused by distinct microbes, of which we must shortly speak. Pebrine—lIn the silkworm nurseries, in which this disease prevails, the silkworms which issue from the eggs, technically called seed, are slowly and irregularly developed, so as to vary greatly im size. Many die OTHER DISEASES OF DOMESTIC ANIMALS. 151 young, and those which survive the fourth moult shrink and shrivel away; they can hardly creep on to the heather to spin their cocoon, and produce scarcely any silk. On an examination of the worms which have died of this disease, De Quatrefages ascertained the presence of minute stains on the skin and in the interior of the body, which he compared to a sprinkling of black pepper; hence the name pebrine. Under the microscope these stains assume the form of small mobile granules like bacteria, which Cornalia termed vibratile corpuscles, on account of their movements. Finally, Osimo and Vittadini ascertained the existence of these corpuscles in the eggs, and consequently showed that the epidemic might be averted by the sole use of healthy eggs, of which the soundness should be established by microscopic examination. It was at about this date, 1865, that Pasteur under- took the exhaustive study of pebrine; but Béchamp was the first to pronounce the disease parasitic, resembling muscardine in this respect, and caused by the attacks of a microbe—or microzyma, to adopt Béchamp’s name—of which the germ or spore is derived from the air, at first attacking the silkworm from without, but multiplying in its interior, and developing with its growth, so that the infected moth is unable to lay its eggs without depositing the spores of the microbe at the same time, and thus exposing the young grub to attack as soon as it is born. Pasteur’s 152 MICROBES, FERMENTS, AND MOULDS. own researches soon induced him to adopt the same view. _ The pebrine microbe was long regarded as a true bacterium, successively described as Bacteriwm bom- bycis, Nosema bombycis (Fig. 72), and i co 0 Panistophyton ovale. Balbiani’s recent 29°70 o researches tend to show that it should 1” oe be assigned to another group, much 0 nearer to animals, and designated Fig. 12, — Nosema Sporozoaria. bombycis, pebrine a % 3 zee ee Sporozoaria.—These protista, still regarded as plants by many naturalists, chiefly differ from bacteria by their mode of growth’ and reproduction, in which they resemble the para- sitic protozoaria, termed Psorospermia, Coccidies, and Gregarinide. In Sporozoaria, growth by fission, the rule in all bacteria, has not been observed; this distinction is fundamental. Sporozoaria multiply by free spore- formation in a mass of sarcode substance (protoplasm), resulting from the encysting of the primitive corpuscles (mother-cells). The formation of numerous spores may be observed within the mother-cells, having the appearance of pseudonavicelle or spores of gregari- nidzand psorospermia (parasites of vertebrate animals). Balbiani forms these organisms, which are found in many insects, into a small group, which he terms Microsporidia. The ripe spores are the vibratile corpuscles of OTHER DISEASES OF DOMESTIO ANIMALS. 153 Cornalia. They closely resemble the spores of some bacilli (B. amylobacter, for instance), and their germi- nation is likewise effected by perforation of the spore at one end, and issue of the protoplasm from the interior. This, however, does not issue in a rod-like form (Bacillus), but in that of a small protoplasmic mass, with amceboid movements, a characteristic not observed in any bacterium (Balbiani). The other species of silkworms which have been recently introduced, notably the oak silkworm from China (Attacus Pernyi), are attacked by microsporidia analogous to those of pebrine. Pasteur has indicated the mode of averting the ravages of this disease. He has thus addressed the breeders: “If you wish to know whether a lot of cocoons will yield good seed, separate a portion of them and subject them to heat, which will accelerate the escape of the moth by four or five days, and examine them under the microscope to ascertain whether cor- puscles of pebrine are present. If they are, send all the cocoons to the silk factory. If they are not diseased, allow them to breed, and the seed will be good and will hatch out successfully. In a word, start with absolutely healthy seed, produced ‘by absolutely pure parents, and rear them under such conditions of cleanliness and isolation as may ensure immunity from infection.” When the disease is developed, fumigation with sulphurous acid is recommended, or preferably with 8 154 MICROBES, FERMENTS, AND MOULDS. creosote or carbolic acid, which do not affect the silk- worms (Béchamp), and which hinder the development of microsporidia. These fumigations likewise keep the litter from becoming corrupt, and in a properly conducted nursery the litter is kept dry. Flacherie—Wrongly confounded with pebrine, the disease flacherie is still more destructive to silkworms. The symptoms are remarkable. The rearing of silk- worms often goes on regularly up to the fourth moult, and success seems assured, when the silkworms suddenly cease to feed, avoid the leaves, become torpid, and perish, while still retaining an appearance of vitality, so that it is necessary to touch them in order to ascer- tain that they are dead. In this state they are termed morts-flats. A few days, sometimes even a few hours, suffice to transform the most flourishing nursery into a charnel-house. Pasteur examined these morts-flats, and found that the leaves contained in the stomach and intestine were full of bacteria, resembling those which are developed when the leaves are bruised in eae ee a glass of water and left to putrefy ‘eo* - & oo (Fig. 73). In a healthy specimen, % fe of good digestion, these bacteria ME ae (Gann. Flachere are never found. It is therefore microbe (x 600 dlam.). evident that the disease is owing to bad digestion, and becomes rapidly fatal in animals which consume an enormous amount of food, and do nothing but eat from morning to night. The digestive OTHER DISEASES OF DOMESTIC ANIMALS. 155 ferments. of unhealthy silkworms do not suffice to destroy the bacteria of the leaves, nor to neutralize their injurious effects. These bacteria are really the cause of the disease, for if even a minute quantity of the leaves taken from the intestine of diseased silkworms be given to healthy specimens, they soon die of the same disease. It is, therefore, essentially contagious, and in order to prevent the diseased silkworms from contaminating the healthy by soiling the leaves on which the latter are about to feed, as much space should be assigned to them as possible. Good seed should also be selected, since it has been ascertained that some lots of seed are more liable to the disease than others. The affection does not indeed begin in the egg, as in pebrine, but the question of heredity comes in. It is clear that when a silkworm has been affected by flacherie without dying of it, its eggs will have little vitality, and the grubs which issue from them will be predisposed by their feeble constitu- tion to contract the disease. 1 or o MICROBES, FERMENTS, AND MOULDS, CHAPTER V. THE MICROBES OF HUMAN DISEASES, I. Microses or Arr, EARTH, AND WATER. It is generally admitted that the large majority of epidemic and contagious diseases which affect men and animals are caused by the. introduction of certain kinds of microbes into the organism.. In reply to the question how these microbes are introduced into the body, and where they are before entering it, it is easy to show that these microbes exist in immense numbers —they or their spores—in the air we breathe, in the water we drink, in the ground on which we tread, and whence there rises, whenever it is dry, a fine dust charged with all sorts of germs, which penetrate together with the air into our mouths and lungs. For a long while we were almost completely ignorant of the conditions of existence of these microbes when they are in the soil or water. The recent researches of Zopf, a German botanist, tend to show that among the inferior algze termed Bacteria THE MICROBES OF HUMAN DISEASES. 157 or Schizophyta, there is a very remarkable dimorphism of mode and habitat. In Beggiatoa of sulphurous waters, for instance, and in Cladothria, which forms a whitish pellicle on the surface of putrefying liquids, Zopf has found, under certain conditions, all the forms designated as Micrococcus, Bacillus, Leptothrix, and Bacterium; that is, microbes strictly so called, in- cluding those which are the producing agents of contagious diseases. Where these algee are found in water or on a damp soil, conditions of existence favourable to their develop- ment, there they live and multiply. But when the soil dries up, when a river returns to its bed after a flood, or a marsh disappears in consequence of the evaporation of its waters, all these alge give forth dormant spores, destined to ensure their propagation. We have described the formation of these spores by concentration of the protoplasm in the interior of each cell; in this form their volume is very small, and they are extremely light, so that as soon as they are desiccated, and then only, these spores are carried away by the slightest breeze and borne to great dis- tances, These are termed air-germs. When these moving germs encounter a favourable medium, at once moist and warm, such as the human mouth or lungs, they fasten there and are immediately developed, first in the form of Micrococeus, then of that of Bacterium, Bacillus, or Leptothria, according to the species to which the spore in question belongs. 158 MICROBES, FERMENTS, AND MOULDS. Schizophyta may therefore have two very different modes of existence, comparable to the heterzecia (change of habitat) and dimorphism of the fungi Ascomycetes and Basidiomycetes. Schizomycetes however, although, like fungi, they obtain their nourishment from organic substances which have been already elaborated, are not true parasites in the first stage of their existence, during which stage they live freely in the water, or on the damp soil. They become true parasites when they penetrate into the blood and tissues of man, in which they necessarily live at the expense of their host. Hence it may be seen why half-dried marshes, meadows from which a river has retreated in order to return to its bed, great excavations of the soil necessary in railway-cuttings, etc., become the source of a large number of epidemic or contagious diseases. In all these places the subsiding waters have left Schizophyta, or microbes in a dried state, and these are soon transformed into dormant spores, which are diffused through the air and enter the mouth and lungs of men living near the rivers and marshes, or who are working on the railway-cutting. The soil which has remained undisturbed for a long while is full of dormant spores, drawn into it by the rain to a greater or less depth; these may preserve their vitality for many years, waiting for the favourable medium which leads to their fresh development. An acquaintance with air-germs, with the microbes of earth and water, has therefore become indispensable THE MICROBES OF HUMAN DISEASES. 159 to the physician and to the professor of hygiene, who are anxious to decide on the precise cause of great epidemics in order, if possible, to foresee and avert them. This new branch of meteorology has been termed atmospheric micrography, since it necessarily involves the use of the microscope. The Microbes of the Atmosphere.—In the observa- tory of Montsouris, Paris, there is now a special laboratory under the direction of Miquel, with the object of studying the living organisms of the air, of establishing statistics of their times and seasons, Figs. 74, 75.—Micrebes and spores of atmospheric dust, mixed with amorphous particles, and collected by the aéroscope. and of drawing general conclusions as to the hygienie condition of the air, according as it is more or less charged with the microbes and spores which are factors of disease. This laboratory is provided with the apparatus necessary for such kinds of research. The first of these apparatus serves to collect the living organisms which are always mingled with a large amount of inert dust (Figs. 74, 75). The 160 MICROBES, FERMENTS, AND MOULDS. apparatus is founded on the principle of the aéroscope, invented by Pouchet for the examination of air-dust. * It consists of a small cylinder in which a current of air is produced by means of an aspirator, on which running, water acts, similar to those in use in all laboratories of physics and chemistry. A thin plate of glass, which has on it a layer of glycerine, is placed at the bottom of the cylinder, so as to intercept the current of air and arrest the dust. The apparatus employed by Miquel at Montsouris is only a modifica- tion and improvement of the one devised by Pouchet. The glass slide is then transferred to the objective of the microscope in order that the dust deposited on it may be examined. This process has enabled Miquel to define the laws which ‘rule the appearance of microbes in the atmo- sphere, and he has been able to calculate their number in a given volume of air. With respect to such fungi and alge as live in our houses (moulds), and on our roofs, walls, and on damp ground (such alge as Peni- cilliwm, Protococcus, Chlorococeus, ete.), he has arrived at the following results, as far as Montsouris, the site of his experiments, is concerned. Few in number in January and February, the number of mould-spores further diminishes in March, and rises again in April, May, and June, in which. month the maximum is attained. The decrease is slow up to October, more marked in November, and the minimum is observed in December. In this case the THE MICROBES OF HUMAN DISEASES, 161 influence of rain and damp is very marked. In winter the average number of spores in every cubic metre of air does not exceed 7000, while in June it rises to 35,000. In summer, however, when the temperature is very high, the number of spores is not great; for this reason, that, in spite of the heat, the air is moist, and the spores settle on the ground, plants, or other objects, instead of floating in the air. On the other hand, in winter, since very cold weather is gerierally dry, the number of air-germs increases. In summer, storms only purify the air for a very short time; within fifteen or eighteen hours alter the rain, the germs reappear, and are five to ten times more numerous than befure. It seems that storms give an energetic impulse to the production of moulds. If we turn to consider microbes, strictly so called, or the bacteria which are the causes of malicnant diseases, research becomes more difficult, on account of their smaller size and great transparency. An expedient is necessary to reveal their presence and enable us to count them accurately: this expedient consists in staining them by various processes, of which we shall speak when we come to discuss the micrographic study of drinking-water. Miquel prefers the process of filtration of the air invented by Pasteur, which consists in passing the air and aqueous vapour into such sterilized liquids as are favourable to the nutrition of microbes. 162 MICROBES, FERMENTS, AND MOULDS. Sterilized Flasks.—Pasteur has shown that air may be deprived of all its germs by being passed through a capillary tube, turned back upon itself. He takes a glass flask and draws out its neck so as to form. a long tube, which is bent in different directions (Fig. 76). The prolonged application of heat expels the air contained in the flask, which is therefore sterilized, and it is then allowed to cool slowly. A Fig. 76.—Pasteur's flask, with bent tube, containing « culture liquid, sterilized. hot culture liquid may now be put into the flask. It must be ascertained, by keeping the flask at a tem- perature of 36° for several days, that the liquid is completely sterilized. The culture flasks are thus fitted to receive the air which is to be the object of study, together with the spores contained in it. Culture liquids—There is a considerable variety of culture liquids: Pasteur’s mineral solution, infusion of hay or turnips, neutral urine, chicken-broth, beef- tea, etc. They should be plunged in a bath heated to a temperature of 150° to 180°, since some spores THE MICROBES OF HUMAN DISEASES. 163 are capable of resisting a prolonged boiling at a temperature of 100°; they still live and are capable of germinating and multiplying when the liquid is cooled. Culture liquids may also be sterilized without the. use of heat, which to some extent affects their nature, by filtering them through a porous substance— biscuit-ware, or a mixture of plaster and amianthus, etc. A more perfect apparatus is employed by Miquel, consisting of a filter of very thick paper, through which the liquid is forced by the simultaneous action of a vacuum on one side, and of strong pressure on the other. For the artificial culture of microbes, solid or partially solid substances are by preference often used, such as gelatine, or slices of potatoes, carrots, hard eggs, etc, prepared in different ways and sterilized before use. We cannot here describe in detail all the processes employed and the precautions necessary in order to avoid error. We must content ourselves with giving the results obtained by Miquel. There are on an average 80 bacteria in a cubic metre of Montsouris air. A hundred of these bacteria includes 66 Micrococci, 21 Bacteria and 13 Bacillt. In rain water there is a different proportion: 28 Micrococci, 9 Bacteria, 63 Bacilli. At the beginning of a thunderstorm, the rain-water includes a consider- able number, about 15 to the cubic centimetre; then the number diminishes, but Miquel states that “after 164 MICROBES, FERMENTS, AND MOULDS. two or three days of damp, rainy weather, the rain- water often contains more bacteria than when it began to fall. Since the atmosphere is then excessively pure, it seems that the bacteria are able to live and multiply in the clouds, or else that the clouds, in their passage through space, take up a varying con- tingent of germs.” The maximum of air-germs is observed in autumn, the minimum in winter; thus, 50 bacteria were counted in December and January, only 33 in February, 105 in May, 50 in June, and 170 in October. Inversely to what occurs with moulds, the number of bacteria, low in rainy weather, rises when all moisture has disappeared from the surface of the soil. The effect of dryness is greater than that of warmth. This explains the scarcity of bacteria after the great rains of February, April, and June. A long drought is, however, unfavourable to their development. Miquel’s experiments lead him to conclude that dew, the evaporation from the soil, is never charged with spores. The dry dust in the neighbourhood of inhabited places, and especially of hospitals, is, on the other hand, charged with microbes. In the centre of Paris, for example, in the Rue de Rivoli, there are nine or ten times as many microbes in the atmosphere as in the neighbourhood of the fortifications. In the Montsouris Observatory, south of Paris, the north winds bring many more bacteria than the south winds. The most impure wind comes from the hills of Villette THE MICROBES OF HUMAN DISEASES. 165 and Belleville, crowded and populous quarters, in which are also cemeteries and slaughter-houses. It has long been established that the air is much purer on high mountains or on the sea, than in plains and in the vicinity of inhabited places. If glass flasks which have been previously sterilized and deprived of air are taken to a great height on the Alps or Pyrenees, and then filled with air, it will be difficult to detect any microbes, and the few which may be found are possibly brought by the observer. So again, on the top of the Pantheon, a cubic metre of air only contains 28 microbes, while 45 are found in the park of Montsouris, and 462 in the centre of Paris. The Microbes of Running and Drinking Water.— Water, whatever be its source, contains many more microbes than air. They are even found in spring- water taken from its source, which shows that they exist in the interior of the earth. The following is Miquel’s estimate, which will give an idea of the quantity of microbes found in Paris water, taken from ‘different places :— Source of water. No. of microbes to the litre, Condensed aqueous vapour ... oa age eee ine 900 Water from drain, Asni@res ... va we aie ses 48,000 Rain-water... we Sei ne des a wee 64,000 Vanne water (Montrouge basin)... _ nee aoe 248,000 Seine water (from Bercy, above Paris)... wee ee 4,800,000 Seine water (from Asniétres, below Pari-) ... ae ses 12,800,000 Sewer-water (from Clichy) ... er ses vee .« 80,000,000 166 MICROBES, FERMENTS, AND MOULDS. These numbers are the minima. The putrefaction of stagnant sewer-water produces germs from which, in a few days, microbes are multiplied by thousands. Certes, in France, and Maggi, in Italy, have lately been occupied with the micrographic study of drink- ing-water. These observers reveal the presence of microbes in the water under examination by means of staining reagents. The reagent most in use is a 15 per cent. solution of osmic acid (Certes). Osmic acid kills the microbes without changing their form, and precipitates them to the bottom of the glass vessel, whence it is easy to collect them. A cubic centimetre of the solution suffices for 30 or 40 cubic centimetres of water. It is allowed to settle, then the liquid is poured off, and the thick, dark-coloured deposit which remains consists of all the organisms previously diffused in the- liquid, and may be examined under the microscope. The only drawback to the use of this reagent is the high price of osmic acid, a matter worth consideration in the extensive and comparative researches necessary in these cases. Maggi obtained analogous results with chloride of palladium, and Certes with iodide of glycerine, and alcoholic solutions of cyanine, gentian, etc.; but none ‘of these reagents are as efficient. as osmic acid, of which the effect is more precise, constant, and durable. Microbes of the Soil—The presence of microbes in the soil has been proved by Pasteur and his fellow- workers, Chamberland and Roux, in the researches into THE MICROBES OF HUMAN DISEASES. 167 the nature of anthrax, of which we have spoken above. These observers collected earth in the neighbourhood of trenches in which animals which had died of anthrax had been buried, and found that not only on the surface, but at some depth, this earth was full of bacteridia (Bacillus anthracis), and also of many other microbes or germs, of which the inoculation might produce more or less dangerous diseases in animals. In order to procure earth in a more perfect state of division, it occurred to Pasteur to collect the excrement of earth- worms, which consists almost exclusively of clay, rich in humus or vegetable earth, on which the worms are nourished. This earth, after passing through the intestinal canal of worms, still contains microbes which have not lost their virulence. As we have already said, spring water, on issuing from the soil, contains microbes which it has acquired in filtering through geological layers; and we have also mentioned the living microbes of chalk, dating, as Béchamp believes, from the secondary epoch. Telluric and Diblastic Theories.—Hence, it is in- telligible that a theory should have been formed, ascribing most epidemic diseases to the influence of microbes of the soil, which can at a given moment enter the human body, first by penetrating into the lungs and digestive organs, and thence into the blood. Two German discoverers, Pettenkofer and Négeli, set forth this telluric theory of disease, and several facts confirm it. It explains why intermittent fever or 168 MICROBES, FERMENTS, AND MOULDS. malaria only prevails in marshy countries when the marshes are partially dry, and especially in summer. In order to make such country healthy, the marshes must be completely dried and filled up, and then transformed into cultivated ground. So, again, the river valleys in France only become unhealthy when the stream returns to its bed, leaving the adjoining meadows transformed into marshes, which gradually dry up and send forth into the air a host of spores, produced by the schizophyta deposited by the water. Finally, great excavations of earth diffuse through the atmosphere the dormant spores brought thither by rain, and remaining in a desiccated state in the soil. In many cases, the intervention of two microbes of different kinds have been assumed to explain the nature and progress of great epidemics, such as cholera, yellow fever, and typhoid fever. This is termed by Nageli the diblastic theory (or that of two producing agents of disease), Thus the microbe of malaria, or intermittent fever, which is not contagious, often predisposes the patient to receive the attacks of another zymotic disease, such as cholera or typhoid fever. The two microbes may subsist simultaneously in the human frame, and their joint action may weaken the organism at the expense of which they live and multiply. Numerous cases might be cited to support this theory, and the following examples may be given :— “Tn the summer and autumn of 1878 the town of Spires was visited by cholera, which was limited to THE MICROBES OF HUMAN DISEASES. 169 the lower part of the town, situated on the banks of the Speyerbach. There was a hospital for old men, situated in the high part of the town, a quarter which remained free from cholera, but 24 out of the 200 pensioners whom the hospital contained were attacked by the disease. Now 38 of these men, the most able- bodied among them, had been employed to dig up some blighted potatoes in a field which lay very low, almost on a level with the water which had collected in a deserted sand-pit. They had not drunk of the water in this field, neither had they passed through the part of the town visited by the epidemic: 20 out of these 33 men had cholera, and only 4 others out of all the inmates of the hospital contracted the disease”’ (Nageli). Observations made on board English transports on the voyage from India give analogous results, “ Detachments of equal number from two regiments embarked on the same steam transport. A few days later, cholera declared itself and carried off many soldiers, all belonging to one of the two regiments, and coming from a camp in which there was a violent outbreak of cholera shortly after their departure. The detachment from the other regiment, coming from a place exempt from cholera, altogether escaped.” Here the influence of the locality and the soil is evident; it was the sole and essential agent of the disease, since the contagion could not have occurred on board ship, in which the conditions are generally healthy, neither 170 MICROBES, FERMENTS, AND MOULDS by contact with the men, nor by that with the clothes and baggage, which were mixed together. The cholera microbe which had been brought on board ship could only act on the detachment mias- matically predisposed by their previous residence in an unhealthy place, containing the malaria microbe (Nageli). Miasma and Microbes.—This leads us to say a few words on the term miasma, formerly in such common use, and now without meaning. Before the existence of microbes and air-germs was known, the doubtful and mysterious principles which were believed to be the cause of virulent and contagious diseases were termed miasmata, and these miasmata were generally supposed to be gases. It is now proved that this cause resides in solid, living particles, the microbes and their germs: the term miasma is less and less employed, or serves to designate air-germs. When, therefore, © Nigeli uses the word, he regards it as synonymous with microbes or air-germs. The Question of Privies—Hence it follows that it is erroneous to apply the name of miasmata to true gases, some of which exert an injurious in- fluence on the human system. Such are sulphuretted hydrogen and ammonium sulph-hydrate which are disengaged from privies, and produce the disease called plomb in the men employed to empty them. These gases are deleterious to microbes as well as to men; microbes cannot co-exist with them, which is perhaps THE MICROBES OF HUMAN DISEASES, 171 the reason why these men seem to enjoy an immunity from most contagious diseases. People are too much disposed, when an epidemic is prevalent, to accuse the privies, of which the emanations are, under ordinary circumstances, only offensive to the smell. When these places, as well as the sewers, are properly constructed, they present no danger. But it is necessary that there should be a sufficient flow of water in both to cover the solid matter. We know, in fact, that if microbes are present, they only become dangerous when dry enough to float in the air. In an epidemic of typhoid fever, for instance, the soiled body and bed linen of the patient are much more dangerous than the privies, in which, however, there is a much larger number of microbes. The linen, therefore, as well as the contaminated rooms and furniture, should be immediately disinfected in the mode prescribed by sanitary authorities. The system of directing everything to the sewer, which is now universally applied to large towns, and which has encountered much opposition, is certainly excellent when properly understood and applied. The cesspools, as well as the cemeteries, ought to be as remote as possible from the houses of the living. It is as much opposed to public health to retain cesspools which are gradually filled in the course of years, in the midst of a town, as to have intramural cemeteries. Everything should be carried off by the sewer, pro- 172 MICROBES, FERMENTS, AND MOULDS. vided there is a sufficient flow of water to take all solid matters with it and completely cover them. These are deposited in places assigned for them, which must necessarily be very remote from thickly populated places. When these matters are then spread over a large surface to dry in the air, the oxygen becomes, as Pasteur has said, the great purifier of microbes. In Paris, some of the sewage water of the great main sewer is diverted on to the peninsula of Genne- villiers, and it is then directed into gutters to serve as a manure for market gardens. After filtering through the cultivated plots, the water flows off in a limpid stream. Cornilleau, whose medical practice is at Genne- villiers, has recently issued a report, showing plainly that the sewage is but a slight source of danger to the inhabitants of the peninsula. During the serious outbreak of typhoid fever which occurred in Paris in 1882, there were only two typhoid cases in the whole commune, and these cases were imported from Paris. II. Micropes oF THE MouTH AND DIGESTIVE CANAL IN A HeatTHy Man. Since there is a profusion of microbes in the air, we can easily understand why they should be found in the human mouth, and hence in all parts of the digestive canal. They are for the most part harmless, THE MICROBES OF HUMAN DISEASES. 173 as long as the epidermis of the mucous membrane covering the intestinal canal is healthy. Pasteur has shown that they are not found in the blood of a healthy man, but that the slightest lesion of the mucous membrane suflices to introduce them into the circulation.* This fact was proved by experiments made at Pouilly-le-Fort on sheep, inoculated with the anthrax microbe by means of their food. The mortality among these animals was notably increased when a 18.—Spirochete buccalis, and S, plicatilis, b (mixed with Vibrio rugula, Figs. 77, eee a), microbes in mouth of a healthy man. : thistles, bearded grain, or sharp-edged leaves were mixed with their food, so as to cause little wounds in their mouths, each of which served as an entrance for microbes. As long as the microbes are few in number, they perish quickly in the blood; but when the number is considerable, the organism has not the power to destroy them ; they soon compete with the corpuscles of the blood, and the most serious diseases ensue. Miquel estimates the number of spores introduced into the human system by respiration, when the health * This is not the case with fishes. Richet and Ollivier have shown that microbes are normally found in the blood of sea-fish, without affecting their health. 174 MICROBES, FERMENTS, AND MOULDS. is perfectly sound, at 300,000 a day, and 100,000,000 a year. It is evident that these germs, always present, may easily become the source of diseases, of which thrush in the mouth of infants, and of sick and dying adults, is one of the least alarming. Sternberg, surgeon of the United States army, 1880, writes: “When I was occupied in the micro- Fig. 19.—Vibrio rugula (Warming) in different stages of development: 0, ¢, f, indi- viduals with vibratile cilia (flagellum); f’, ciliated spores. Found in the human mouth and intestines. scopic examination of foul river water at New Orleans, I used to find in my own mouth almost. all the organisms which were present in the putrefying liquid I was examining—Bacterium termo, Bacillus subtilis (Fig. 80), Spirillum undulatum,and a variety of minute spherical forms and of rods, difficult to classify except under the generic names of Micrococcit and Bacteria. Another organism which I have often found in healthy human saliva is a species of Sarcina, perhaps identical with S. ventriculi.” But the organism most commonly found in the human mouth, which attracts attention from its large THE MICROBES OF HUMAN DISEASES. 175 size and its abundance, is Leptothria buccalis. It is never absent from the rough surface of the tongue or the interstices of the teeth, and even those persons who make a frequent use of the tooth-brush are not exempt from it. In the latter case, however, it only appears in the form of short, scattered rods; while in G Wo My, YE AS aE MY h Ye Libis bi aey NNN Mi Y “pf a gee \ \ if i s SARS Fig. 80.—Bacterium (Bacillus) subtilis (Zupf). in different stages: A. ciliated rods ; E, F, spores; G, Zoogloea. In infusions of hay, and in the human mvuth (much magnified). i! ie YY nhs ail other cases, the tufted stems of its vigorous growth abound in the saliva, and are often established on the epithelial cells, whence they may be detached by friction. Sternberg compares the human mouth to a culture apparatus, in which the germs of microbes find an even temperature and the moisture necessary for their development naturally provided for them—conditions which can only be artificially produced in the laboratory. 176 MICROBES, FERMENTS, AND MOULDS. III. Toe Virvutent Micrope or Heatray Human SALIVA. Pasteur and Vulpian in France, and Sternberg in America, discovered almost simultaneously that the human saliva may, under conditions with which we are still imperfectly acquainted, become virulent, and that this virulence is due to the action of a Micrococcus, normally present in the saliva, a microbe quite distinct from that of rabies, of which we have already spoken. It is only known that this micrococcus is very common in the saliva of a healthy man, and that in some individuals the saliva is exceptionally virulent. When injected under the skin of healthy rabbits, it produces grave affections, often resulting in the animal’s death. These affections are due to the presence of the micrococcus, since the saliva becomes harmless as soon as these organisms are removed from it. Sternberg informs us that his own saliva is among those which possess this curious and alarming property. He regards the more abundant nutriment which this microbe finds in the mouths of some persons as the cause of this virulence, since thus its development is more energetic. “In my own case,” he writes, “there is a very abundant secretion of saliva. ... My culture experiments show that this micrococcus multiplies very rapidly, and in virtue of this faculty it has for a certain time the advantage THE MICROBES OF HUMAN DISEASES. 177 over Bacterium termo, which appears to be fatal to the former when present in any number.... In my culture flasks, a small drop of blood from an in- fected rabbit gave birth within a few hours to such a number of microbes that the liquid contained in the flask was completely filled with them, and it was deprived of the nutriment necessary for any further development.” The exceptional virulence of this microbe must therefore be ascribed to its vital and reproductive energy, and to the rapidity with which it multiplies ; at any rate, until we know more on the subject. IV. The Microses oF DENTAL CARIES. Miller’s recent researches (1884) tend to show that dental caries is chiefly due to the development of one or more species of bacteria. The presence of acids introduced into the mouth, or developed by certain diseases (ulcers, thrush, etc.) which are themselves produced by microbes, appears to be the predisposing cause of this affection. These acids begin by scttening the dentine, deprived at some point of its superficial coating of enamel, and through this the bacteria enter. Saliva can be rendered experimentally acid by mixing it for four hours, at a temperature of 20°, with sugar and starch (Cornil). Hence the injuriousness of sugar- plums and other sweetmeats, long and correctly 9 178 MICROBES, FERMENTS, AND MOULDS. supposed to be the cause of the early decay of teeth, especially in children who eat them in excess. The microbe which Miller has found to be most common in de- cayed teeth is very polymorphic. Microccocus, bacterium, chains and filaments, are only different phases of the same plant, which also pro- duces acid fermentation in the mouth, and the formation of lactic acid. Within the dentine tubules, a section examined under the microscope shows all the inter- mediate stages between the isolated "Gris In the. dentine micrococcus and the filaments b, spontaneous caries. (Figs. 81, 82). Miller succeeded in producing this disease in sound teeth artificially. ; 6 i at oe 0 § H \e 0 ° o CY % %, 2 eats G.-re 2 Sav Qe pee co? o oOo oO o ° » fo) Fig. 82.—Bacterium of dental caries ae b, different forms obtained in gelatine culture, According to his experiments, the best dentifrice for _ THE MICROBES.OF HUMAN DISEASES. 179 the destruction of microbes is a solution of corrosive sublimate (mercuric chloride), one part in 1000, which can be further diluted by four parts of pure water. V. Microzses oF INTERMITTENT OR MALARIOUS FEVERS. We say microbes in the plural, since it is almost certain that the different types of intermittent fever, tertian, quartan fever, etc, are produced by different microbes; moreover, it is probable that these microbes vary with the locality. That of intermittent fever in France is probably not the same as that of the malaria, or fever of the Pontine marshes in Italy.; and the African fevers, again, are probably produced by a different organism. Intermittent fevers are the first internal diseases of which the vegetable parasitic nature was sus- pected. Before that time we were only acquainted with the parasites of the skin, and with the entozoaria and epizoaria (intestinal worms, lice, acari, etc.), which areanimals, In 1869, Dr. Salisbury, of Cleveland, U.S., entered on researches which led him to the con- clusion that intermittent fever in the marshy valleys of the Ohio and the Mississippi must be ascribed to the presence in the system of a filamentous alga which approximates to the genus Palmella, The spores of this alga are constantly found in the saliva 180 MICROBES, FERMENTS, AND MOULDS. of the subjects of intermittent fever. By exposure during the night of little glass plates in marshy meadows, Salisbury was able to collect similar spores, which settled on the lower surface of the glass, an‘ were found floating in the drops of condensed dew.* On passing through these marshes in the evening, there was a peculiar sense of dryness in the throat, and expectoration revealed the presence of spores of Palmella. Finally, earth taken from these marshes was found to be full of the same organisms. When the marsh begins to dry up, the spores are produced in abundance, and intermittent fevers occur. Salisbury writes that “in 1862, the weather was very wet until about the Ist of July; but that during July, August, and September, there was hardly a drop of rain. The springs and water-courses were nearly dried up, the marshes and wet grounds also became dry, vegetation was almost completely arrested, and the whole country presented an arid appearance. Shortly after the drought began, intermittent fever made its appearance in all the unhealthy districts, and spread so rapidly during the months of July and August, that it attacked almost every family living on marshy ground. “A low, peaty meadow extends along the canal * We must repeat what has been said before, that the presence of these apores in the air is quite independent of that of the vapour which constitutes dew; in other words, the vapour does not transport these spores, which must, on the contrary, be perfectly dry before they can float in the air and settle on any dump object. THE MICROBES OF HUMAN DISEASES. 181 to the south-east of the town of Lancaster, and the neighbouring valleys are low and damp. The third quarter of the town, touching on this meadow, and all that part which is not raised from 35 to 40 feet above the level of the meadow, have always been districts in which attacks of intermittent fever are prevalent. Those who live near the marsh are liable to annual attacks of fever from May to November. In August and September these attacks are generally the most severe.” We said that moisture does not favour the trans- port of microbes and their spores through the air, but the remark does not apply to fogs, in which numerous spores are found. We know that fogs are formed of minute globules of water, which float in the atmosphere, and of which the vapour of our breath, only visible in cold weather, can give us an idea, These globules of water float in the air just as spores and all kinds of dust do, without wetting the spores or running together, since as soon as this occurs, the fog ceases to be; it is condensed, and falls in.the form of more or less fine rain. Salisbury has ascertained that there is a certain connection between fogs and intermittent fevers, and this explains why people are more apt to contract fever in the morning and evening, at which times there is in summer always a fog floating to a varying height above marshy places. Tn a farm near Lancaster, the farmer and his wife, who slept on the first floor, were attacked by tertian fever, 182 MICROBES, FERMENTS, AND MOULDS, while their seven ‘children, who slept on the second floor, escaped. Salisbury ascertained that there was a fog every morning, rising from a reservoir which had been recently made. This fog reached the house and rose above the first floor, but not as high as the windows of the second floor, and penetrated into the parents’ bed-chamber through the open window. This vapour had the same smell as the marsh, which was covered with fever algze (Palmella febrilis), and pro- duced the same feverish dryness in the throat and pharynx. The vapour dispersed soon after sunrise, and before the children had left their chamber. Salisbury likewise ascertained the polymorphism of Palmella febrilis, a polymorphism which is con- firmed by the recent observations of the skilful naturalist Zopf, and this fact explains the mode in which an aquatic alga can live in the human blood, in the form of Bacillus or Spirillum. Still more recently (1879), marsh fever, or malaria, which is so common in Sicily and in the Roman Campagna, have been studied from the same point of view by Crudeli, Cuboni, Cecci, and others, who ascribe the disease to a vegetable parasite which they call Bacillus malariw. This bacillus is abundantly found in the blood of patients during the period of attack, while during the period of acme which ter- minates each attack only spores are found. The same microscopic organism is found in all the malarious districts of the Roman Campagna, and it can be THE MICROBES OF HUMAN DISEASES. 183 produced in artificial cultures. It is not found in the healthy parts of Lombardy. In the strata of air which float above malarious ground in summer, this microbe is so common that it is found in abundance ; in the sweat of the forehead and yi) hands (Fig. 83). This organism is not only y capable of cultivation, but rabbits and dogs can be inoculated with Fig. 83.—Malaria bacillus it, So as to produce marsh fever aceon in them.* The lesions which are observed in an autopsy are the same as those in man, showing that the site preferred by the microbe is the spleen and the marrow of the bones. The fact that the bacillus and its spores are suc- cessively found in the blood explains the intermittent type of the disease, tertian, quartan, etc., according to the variety of marsh fever. According to its variety, and perhaps to the species of Schezophytum, the com- plete evolution of the plant sometimes demands 48, sometimes 72 hours, and the access of fever always corresponds with the period of greatest activity in the, bacillus—that which precedes the emission of spores. Two military surgeons, Laveran and Richard, * It is generally believed in France that animals, and especially herbivora, cannot contract intermittent fever. This opinion is erro- neous. It is known that in Italy cattle contract this fever when they are not acclimatized to marshy districts, and that they are cured by sulphate of quinine. 184 MICROBES, FERMENTS, AND MOULDS. have also observed the parasitic nature of intermittent fever in Algeria. The organism which they have constantly found in the blood of those affected by marsh fever presents several different aspects, but appears especially to attack the red corpuscle of the Fig. 84.—Parasite of intermittent fever ( A de : A, normal hematin; B, B, corpuscle No.1; C, corpuscle No, 2, motionless; TD), corpuscle No. 2, containing mobile pigmented grains ; Ki, corpuscle No. 2, provided with mobile filaments; G, detached mobile filament; H, H, corpuscle No, 3; I, K, corpuscle No. 2, of small size, red and agglomerated; 1, L, hematins to which the small corpuscles No. 2 are attached; M, pigmented leucocytes, their nuclei made visible by carmine. blood, in which, according to Laveran’s expression, “it is encysted like a weevil in a grain of wheat.” THE MICROBES OF HUMAN DISEASES. 185 This observer thinks that it approximates to the algee of the genus Oscillaria * (Fig. 84). The different forms taken by this organism are only the successive phases of its development, and have not yet been observed by a competent botanist, who alone can indicate precisely their true nature. At a certain period of its existence the parasite attaches itself to the red corpuscle of the blood, and is nourished at its expense. The corpuscle turns pale, loses its colouring matter, and disappears, leaving as residue a small grain of pigment, representing the hemoglobin absorbed by the parasite. Two or three mobile filaments arise from the encysted parasite, which resemble vibrios, and move rapidly in the blood as soon as they become detached. Laveran states that he has found the same organism in malaria patients at Rome; and Richard found them in the blood of a sailor just returned from China, who was suffering from intermittent fever. The use of the microscope permits an accurate diagnosis of this disease. The spherical bodies, or the microbe in its encysted form, announce that the attack is imminent, and no time should be lost in administering sulphate of quinine. Richard writes that “the multiplication of these bodies must be extremely rapid. For instance, in tertian fever they are not found in the intervals of the attacks (apyrewia). As the attack approaches, * Revue Scientifique, April 29, 1882, p. 527; Januar, 27, 1883, p 3. 186 MICROBES, FERMEN‘IS, AND MOULDS. they appear in increasing numbers, and their maximum corresponds with the beginning of the rise in tempera- ture; from that moment they begin to perish, since the heat of fever is fatal to them, ‘and completely checks their development. This explains the inter- mittent character of the disease. They produce fever, the fever kills them and then subsides ; when apyreaia occurs they multiply again, excite fever, and so on.” Thus there is a successive series of auto-infection by the parasite itself, unless its development is arrested by sulphate of quinine. “The parasites of typhus and typhoid fever are not affected by a temperature of 40°, and even of 42°, and hence the continuous character of these fevers.” Cornil has, with some justice, criticized Laveran’s description and illustrations of the parasite of marsh fever. It is difficult to recognize in it an organism really belonging to the animal or vegetable kingdom. The form of the filaments which, as he asserts, issue from the so-called encysted bodies, resemble those which Hoffmann has seen and drawn in blood in its normal state, and also in various diseases, and are probably only expansions of extravasated protoplasm in the red corpuscles at a temperature of 40°. The encysted bodies are also, according to all appearance, only blood-corpuscles, more or less affected by disease. There only remain the pigmented, encysted granules in the red and colourless corpuscles, granules which have been observed by others, and especially by THE MICROBES OF HUMAN DISEASES. 187 Marchiafava and Celli. But experiments undertaken to show that these granules are microbes have as yet afforded no certain results, In short, Cornil remarks: “Since bacteria are found neither in the internal organs nor in the blood of those who die of intermittent fever, we are tempted- to suppose that the virulent agent resides in the sur- face of the mucous membrane—for example, in that of the digestive canal; and that the chemical poisons pro- duced under the influence of these micro-organisms penetrate thence into the blood. They then act on the red corpuscles of the blood.” Finally, we must remember that many continuous fevers, especially those of hot countries, seem to be complicated by the presence of two parasitic elements, as we have said in describing Nageli’s diblastic theory. To the marsh microbe, which comes from the soil, another is added, of which the immediate origin is due either to direct contagion, or to some other telluric or atmospheric local influence. VI. REcURRENT FEVER AND YELLOW FEVER. “We place these two diseases together, simply because they have rarely been observed in France. Recurrent fever, or relapsing typhus, is a disease which has been observed in Germany, Russia, Ireland, and India, in which latter country it is called jungle 188 MICROBES, FERMENTS, AND MOULDS. fever. In all these countries poverty, scarcity, and famine appear to be the predisposing causes. In this case, the presence of microbes in the human blood has been established in the clearest and most incontestable way. This discovery was made by Virchow and Obermeier in 1868, but nothing was published on the subject until 1873. The symptoms of the disease are very like those of typhoid fever. The microbe, which may always be found in the blood, and which characterizes the disease, is a Spirillum or Spirochate (S. Obermeiert) ; that is, a filamentous organism, twisted into several spirals, and animated by very lively movements (Fig. 51, m, 0). These spirilla may be seen moving in thousands among.the blood-corpuscles, when these are placed under the objective of the microscope. The difficulties experienced by the original observers in their attempts to inoculate man or animals with the disease, and the fact that in some cases the microbes appear to be absent from the blood of affected persons, have thrown some doubt on the relation between the disease and its microbe. This is because the conditions of the existence of’ this plant in the system were not sufficiently con- sidered. Albrecht has recently shown (1880) that blood which apparently contains no spirilla will, if kept in a culture-flask for some days, protected from air-germs, become full of these organisms at the end of that time, a proof of the pre-existence of the spores THE MICROBES OF HUMAN DISEASES. 189 The same observer was able to point out the spores, which are only visible under a magnifying power of 1000 diameters, and which succeed to the spirilla during the remittent period. Moreover,a monkey was successfully inoculated with the disease at Bombay, and after the lapse of five days spirilla were found in the animal’s blood. Yellow fever has not yet been sufficiently studied in the countries in which it prevails, but there can be no doubt that it is likewise produced by a special schizophytum. Originating, as it appears, in North America, probably in the delta of the Mississippi, this disease has been spread by maritime commerce over the whole intertropical zone of the globe. The centres of infection are always on the sea-board, at the mouths of great rivers, from which we conclude that its special microbe is found in its free state in the brackish marshes formed at river-mouths. The medical men of Rio de Janeiro, and particu- larly Freire, have lately described and published illus- trations of microbes said to have been observed by them in the feces of patients attacked by yellow fever. But their drawings are for the most part fanciful, and betray great inexperience in the methods of research and in microscopic examinations; for instance, the air-bubbles, unskilfully interposed in the preparations which their author thought worthy of photographic reproduction, figure as microbes. Thanks to the accuracy of photography, which leaves 190 MICROBES, FERMENTS, AND MOULDS. no scope for the fancy of a draughtsman, there can be no doubt as to the gross error committed by the observer. As for Freire’s attempts at vaccination, his own statistics are far from being favourable to his method ; in fact, they prove that vaccination increased the rate of deaths in the proportion of 19 per 100. Much more scientific researches, were undertaken Fig. 85.—Section of Kidney in yelluw fever (Babés), showing a capillary vessel, c, filled with chapicts of micrococci. by Cornil in Paris, on some anatomical preparations, preserved in alcohol, which were sent from Brazil. He found in the liver and kidney of the victims of yellow fever, chaplets of micrococci or bacteria (Fig. 85), only visible under a very strong magnifying THE MICROBES OF HUMAN DISEASES. 191 power (more than 1000 diameters). But they are not invariably present, and it is consequently uncertain whether they are the cause of the disease. From its symptoms and lesions, there is reason to think that the parasite or parasites—for there may be several, according to Nigeli’s theory—have their seat in the digestive canal. New and sustained researches, carried on in countries where yellow fever prevails, and more methodically conducted, are necessary to elucidate this question. VII. TypHorp anp TypHus FEVERS. These two diseases may be taken together, since in both the digestive canal is the part chiefly affected. Here crowding, the aggregation of men and the human miasmata resulting from it, play the chief part, admitting, as we have already said, that miasma means microbe. We need not, therefore, deny the in- : fluence of predisposing conditions, or what is called receptivity for the disease. These unfavourable con- ditions are: physical exhaustion, bad food, youth, mental emotion—all which conditions are allied with human miasmata, the result of crowding in barracks, where typhoid fever prevails; in camps, which are more subject to typhus; and in the badly built houses of our large cities. In few diseases is the influence of anti-hygienic 192 MICROBES, FERMENTS, AND MOULDS. conditions more apparent. Want of air and cleanli- ness is one of the principal factors of these cruel epidemics. In the confined lodgings of the artisans of large cities, the dead, the sick, and the healthy man may be found sharing the same room and even the same bed; linen inapregnated with typhoid ex- cretions may remain for days in the same chamber. The walls and floors of our barracks, too rarely cleansed, disinfected, or whitewashed, harbour myriads of mi- crobes; and the water of adjoining wells likewise con- tains them in great numbers. Nor can it be said that hygienic conditions are more carefully observed in the rural habitations of villages and detached farms. The peasant is as ignorant of the laws of health and cleanliness as the artisan; the neglect of the builder, often a mere mason, of the landlord and the tenant, is still more striking in country districts. For this reason epi- demics are generally more fatal in the country than in towns; but they are less frequent, of shorter dura- tion, and more easily localized in a village or detached farm, since in this case there is a large supply: of oxygen, which is the great destroyer of microbes. With respect to typhoid fever, one of the most common diseases in this country, the lesions by which it is always characterized show that the microbe pro- ducing it is chiefly found in the mucous membrane of the intestines, in Peyer’s glands, and in the isolated follicles which cover this membrane, and which are THE MICROBES OF HUMAN DISEASES. 193 always hypertrophied and softened in typhoid patients. The round red spots which may be observed upon the skin are distinctive marks of the affection of the diges- tive canal, and it has occurred to Bouchardat that if, as he supposes, these spots contain the same microbe as that of the intestines, it might be cultivated and attenuated into a true vaccine. The presence of special microbes in typhoid fever was first observed by Recklinghausen in 1871, but the exact description of the typhoid bacillus has been only recently given by Eberth and Klebs. Eberth has observed this bacillus in the spleen, the lymphatic glands, and the intestines, making use of special staining processes. It appears in the form of short rods with rounded extremities, in the tubular glands and round the bottom of these glands, which cover the mucous membrane of the intestine. They are numerous when the ulceration of Peyer’s glands begins; afterwards they become fewer, and are succeeded by other microbes. From the position of the bacteria in a section of the mucous membrane, it may be seen that they penetrate through its surface, and fasten on the ulcerated and mortified tissue (Cornil). Blood taken from living patients often displays bacilli amid the red corpuscles (Fig. 86). The spleen, which is always hypertrophied, contains the same bacillus, which is also found in the liver, and some- times in the kidneys and urine. 194 MICROBES, FERMENTS, AND MOULDS. Many other bacteria appear in the intestines when the disease is approaching its end, but the bacillus in question is the only one found in the blood and internal organs, so that it is really characteristic of the disease. Gaffky, a German micrographist, and a pupil of Koch, has succeeded in the artificial culture of this microbe, taking it from the spleen of persons who died of typhoid fever. It is actively developed on gelatine and potatoes, becomes very lively and produces endo- FESO Q es is Fig. 86.—Bacilli of typhoid fever (x 1500 diam.): three red corpuscles may be observed in the sume preparation. genous spores at a temperature of 38°. But the inocu- lation of animals with the disease has hitherto been unsuccessful, at least so as to reproduce in them an affection of the intestines, really resembling that of Peyer’s glands in man. The horse is the only animal affected by a similar. disease, which has also been called typhcid fever. In 1881, the horses of the Paris Omnibus Company were decimated by an epidemic of this nature. But the lesion of Peyer’s glands cannot be compared with that which occurs in the same glands in man, and no special microbe has yet been discovered. THE MICROBES OF HUMAN DISEASES. 195 The presence of the bacillus of typhoid fever in the air or in water has not yet been ascertained. Neither is anything known about the microbe which may be assumed to be the cause of typhus fever. VIII. Tart CHoLtera MICROBE, This terrible disease has its origin in Asia, where its ravages are as great as those of yellow fever in America. It is endemic or permanent in the Ganges delta, whence it generally spreads every year over India. It was not known in Europe until the begin- ning of the century; but since that time we have had six successive visitations, and it seems destined to replace the plague or black death of the Middle Ages, a disease which appears to be now confined to some few localities of the East.* In 1817, there was a violent outbreak of cholera at Jessore, India. Thence it spread to the Malay Islands, and to Bourbon (1819); to China and Persia (1821); to Russia in Europe, and especially to St. Petersburg and Moscow (1830). In the following year it overran Poland, Germany, and England, and first appeared in Paris on January 6, 1832; here it raged until the end of September. * See in the Annuaire de thérapeutique, 1885, Bouchardat’s account of cholera epidemics in Paris, together with remarks on the nature, the parasite, the hygiene. and the treatment of cholera, 196 MICROBES, FERMENTS, AND MOULDS. In 1849, the cholera pursued the same route. Coming overland from India through Russia, it appeared in Paris on March 17, and lasted until October. | In 1853, cholera, again coming by this route, was less fatal in Paris, although it lasted for a longer time —from November, 1853, to December, 1854. The three last epidemics, 1865, 1873, and 1884, differ from the foregoing in not having taken the continental route; they came by the Mediterranean Sea. Brought from India to Egypt by the Mecca pilgrims, the epidemic of 1865 entered France by way of Marseilles, ravaged Provence during the summer of 1865, and was carried to Paris towards the end of September by a woman who came from Marseilles. It was less fatal than the preceding epidemics, and se also was that of 1873. The epidemic of 1884 took the same route. First localized in Alexandria (1883), it attacked Naples, Marseilles, and Toulon in the summer of 1884, and overran all Provence; thence it was transferred to Nantes, to several towns in the north-west of France, and to Paris, where it was comparatively mild. Finally, it entered Spain at Barcelona towards the end of the year, and ravaged the whole peninsula through the summer of 1885. In August, it also reappeared in Marseilles and Toulon, and this could not be ascribed to a fresh importation from Spain or the East. The essentially epidemic and contagious progress THE MICROBES OF HUMAN DISEASES. 107 of this disease clearly indicates the presence of a microbe, of which the chosen seat is the intestines, whence it passes with the patient’s feeces, and con- stitutes the contagious element in places affected by the epidemic. The first precise micrographic researches made on this subject were those of the French and German commissions sent to Alexandria in 1883. Koch, member of the German sanitary commission, was the first to describe the microbe which it has been decided to consider as the producing agent of cholera. He gave it the name of comma bacillus (Bucillus komma), on account of its form. In order to see these bacilli in any number, a case of malignant cholera must be observed. For this reason, an unsuccessful search for this parasite has often been made, since it cannot be distinguished from the numerous other parasites found with it in the intestines of cholera patients on the second or third day. A small fragment of the rice-watvr evacuation of cholera should be placed on a glass slide and stained with methyl violet or methylene blue; the superfluous liquid must be drained off, and the pre- paration may then be examined under a magnifying power of from 1200 to 1500 diameters, making use of an immersion lens, on which light is thrown by an achromatic condenser. The comma bacilli then present the appearance shown in Fig. 87, and, in spite of the colouring matter, 198 MICROBES, FERMENTS, AND MOULDS. are full of motion and activity, which they retain for some time. They are arched in form, and, roughly speaking, resemble a comma. Their length is 1} micro- millimetres to 24 micro-millimetres, and their width is 0°6 to 0-7 micro-millimetre. They are often arranged in chains or chaplets, so as to appear like the letter 8S, or several S’s, placed end, to end as we see in Fig. 87. These latter are the most characteristic. Compared TNS earn he Brosh aoe cvion lina sella Qrewelp Magalies ie ealvates of bacillus, under a simple lens. with the microbe of tuberculosis, that of cholera is shorter and thicker. Its spiral shape has led to the belief that it is an intermediate form between the genera Bacillus and Spirillum. Comma-shaped microbes may be found in most stagnant and running water, but they are in general much larger, and none of them present the charac- teristic dimensions of Bacillus komma. This bacillus is found in the riziform grains of choleraic evacuations, which are, as we know, formed THE MICROBES OF HUMAN DISEASES. 199 by the desquamation of the mucous membrane of the intestines. The membrane is, in fact, literally flayed from one end to another, and, in consequence of its congestion, the walls of the intestines are of a bright rosé colour. The riziform grains consist of small tufts of epithelial cells, conglomerated together, and they contain numerous bacilli. They are also found in the glands of the intestine into which they penetrate, owing to the desquamation of the epithelium. They have not as yet been found in the kidneys, the urine, or the blood. Cultures of this microbe on gelatine or gelose are very successful. Koch has observed that it readily multiplies in damp linen, or in milk, broth, eggs, moistened bread, potatoes, etc. The temperature most favourable to it is from 30° to 40°, and even at 20° it still multiplies on gelatine. Below 16° it grows very slowly, but does not perish. Cold does not kill it: at 10° below zero it is still alive, and capable of resuming all its activity when replaced in favourable conditions. This microbe is aérobic, and soon dies when deprived of air. Water can serve as its vehicle, but does not supply sufficient nutriment, so that it soon disappears. This, however, is not the case with stagnant water containing organic matter. When the level of sub- terranean waters sinks, the surface water becomes more charged with all kinds of refuse, and the multiplication of germs becomes more easy. Bacilli 200 MICROBES, FERMENTS, AND MOULDS. cultivated in distilled water die within twelve hours, while they can live for a week in drinking-water. (Cornil.) The influence of the level of the subterranean waters on the progress of cholera epidemics was pointed out in Germany by Pettenkofer long before there was any serious idea of regarding a microbe as the cause. During his recent travels in India, Koch met with the comma bacillus in the stagnant waters of that country. For a long while the attempt failed to reproduce Asiatic cholera in animals by injections of comma bacilli, and thus to prove the parasitic nature of the disease. The animals in countries attacked by cholera appear to enjoy immunity in this respect. Nicati and Rietsch at Marseilles were, however, successful in pro- ducing cholera by the direct injection of choleraic liquid into the duodenum of guinea-pigs, dogs, ete. Almost, all these animals died at the end of two or three days, and the inflamed intestines contained a number of comma, bacilli, much more vigorous than those of the injection. Bochefontaine, of Paris, swallowed pills which contained choleraic evacuations. He felt unwell for some days, but no serious consequences ensued. It is probable that in this case the acidity of the gastric juice attenuated, or partially destroyed the bacilli. We shall see that acids are, in fact; adverse to the THE MICROBES OF HUMAN DISEASES. 201 development of the microbe. Bochefontaine also injected the choleraie virus under the skin of his arm, but the operation was only followed by an cedematous redness, localized round the puncture, and the con- stitutional symptoms were not so marked as those produced by taking the same virus into the digestive canal. Ferran’s Attempts at Inoculation—This leads us to mention the attempts at inoculation made by Ferran on a large scale in Spain, under the name of anti-cholera vaccinations. In 1884, Ferran, a Tortosa physician, was sent by the municipality of Barcelona to study the infectious agent of cholera at Toulon. His preceding studies in micrography pointed him out for this mission. He returned from Toulon, provided with cultures of the comma bacillus, and devoted himself to the study of its life-history. The facts reported by him differ very much from those previously observed, and cannot be accepted without further investigation. According to Ferran, the cholera microbe presents a polymorphism which has escaped notice in Koch’s investigations, and those of the other micrographists who have observed and cultivated it. When trans- ferred to a sterilized alkaline infusion, the comma bacillus increases in length, forms sinuous filaments, then swells at one extremity until it attains to the volume of a red blood-corpuscle, thus constituting an oogonium filled with protoplasm. A transparent 10 202 MICROBES, FERMENTS, AND MOULDS. envelope (periplasma) then encloses the oogonium, which thus becomes an oosphere. Close to this, on the original filament, a small swelling appears, which Ferran regards as the pollinidium, or antheridium, which is intended to fertilize the oosphere and trans- form it into an oospore. When the rupture of the oospore occurs, the granules contained in it float in the liquid. Those which have been fertilized grow until they are as large as the original oogonium, and constitute mul- berry-shaped bodies, so called on account of the numerous round projections or micrococci which cause the surface to resemble that fruit. A very slender filament may soon be seen to issue from one of the points of this mulberry-shaped body, a filament which grows longer, and sometimes two of them appear at once. These filaments’ become sinuous, twist in spirals, form spirilla, and are then segmented so as to form by fission Koch’s comma bacilli, which are the starting-point of the culture, and of this cycle of evolution (Figs. 88, 89, 90). Hence it would appear that the cholera microbe must belong to a much higher group than that of bacteria, to which it has been hitherto assigned. This mode of reproduction would show that it is not an alga, but a fungus of the group of Peronosporew, and it is, in fact, termed by Ferran P. Barcinone while his friends prefer to call it P. Ferrani, after its discoverer. THE MICROBES OF HUMAN DISEASES. 203 Ferran regards this peronospora as the infectious agent of cholera. Yet it seems extraordinary that such a remarkable polymorphism should have escaped the observation of Koch and of the numerous micro- Figs. 88, 89, 90.—Evolution of cholera microbe (Peronospora Ferrant: Ferran): 1, Cholera microbe (Bacillus komma), discovered by Koch. 2. Spiral form of pacillus, transferred from gelatine to an infusion. 3. Degeneration of spiral form after a series of successive cultures. 4. Cholera microbe (Peronospora ant): develop of oogonium on the spirilla and straight filaments. 5. The oogonium is filled with granules which centre in a point k, and it is then converted into an oosphere ; m, pollinidium on fertilizing organ. 6. The cosphere is converted into mulberry-shaped and comma-shaped bodies. graphists who have made various cultures of the comma bacillus. It is difficult not to suppose that some negligence or error has vitiated Ferran’s re- 204 MICROBES, FERMENTS, AND MOULDS. searches, and the first idea which will occur to any unprejudiced micrographist, is that P. Ferrani is not really Koch’s comma bacillus, and consequently not the cholera microbe.* We have, in fact, already shown that numerous comma-shaped bacteria, or free cells, are found in water and in the human body, and that these may be easily confounded with the true comma bacillus when staining reagents and a very precise mode of culture are not employed. Ferran himself states that this staining process must not be used in the culture of P. Ferrani. Cornil has, however, shown that the true comma bacillus is not destroyed by methyl violet. Finkler had previously discovered in cholera nostras, which is not epidemic, a comma-shaped microbe resembling in many respects the one described by Ferran. Koch has shown that this microbe, as well as one of similar form found by Lewis in the saliva, does not act in cultures like the microbe of Asiatic cholera; Lewis’s microbe does not, like the cholera bacillus, liquefy gelatine. The precautions necessary for the sowings of culture liquids are so great that we may be permitted to doubt whether Ferran has always guarded.against error. Brouardel’s report shows, after a visit to * Onur criticism on the description and illustrations of Laveran’s marsh-fever microbe might be applied, word for word, to Ferran’s description and illustrations of the cholera microbe, which we have reproduced above. THE MICROBES OF HUMAN DISEASES. 205 Ferran’s laboratory, that the instruments and methods in use there were primitive and insufficient. Until these facts have been confirmed by other observers, it seems prudent to regard P. Ferrani and B. komma as two absolutely distinct microbes. It does not follow that the culture liquids employed by Ferran did not contain the latter, but it is probable that it also contained, and in larger numbers, a second microbe (?), which is Peronospora Ferrani. It may: also be observed, the injection of Ferran’s culture liquid into the intestines of guinea-pigs pro- duced no effect, while subcutaneous injections soon killed these animals and distinctly affected men. This is precisely the opposite effect to that observed by Nicati and Rietsch at Marseilles, and by Bochefontaine in Paris. This is a crucial difference, since it shows that the two microbes are not identical, and all our know- ledge of cholera tends to show that its microbe has a special action on the intestines.* However this may be, Ferran carried on his culture experiments in the endeavour to obtain an attenuated microbe which might serve for preventive inoculations. He believes that he has succeeded, and * The experiments made by Gibier and Van Ermengen in August, 1885, confirm this opinion. After inoculating a certain number of guinea-pigs, according to Ferran’s hypodermic method, with a virulent culture liquid, and giving them time to recover, the same liquid was injected into the stomach of these animals, and they all died with the symptoms and lesions of cholera 206 MICROBES, FERMENTS, AND MOULDS. after inoculating himself, he performed the same operation on several of his friends; then on thousands of people in different towns of the province of Barce- lona, and throughout Spain. His inoculation consists in introducing, by means of the small syringe used for hypodermic injection, about a cubic centimetre of the vaccinal liquid, the nature of which is kept secret by its author. There is always a certain discomfort after the operation, but it disappears at the end of a few hours, Ferran himself states that one inoculation will not suffice to ward off the contagion. A second, third, and even more, are necessary for the attainment of this object, but the discomfort caused by the operation always becomes less. Up to this time the results obtained by the pro- cess during the recent epidemic in Spain are not accurately known, since Ferran has been unable to produce the official statistics which are necessary to confirm his assertions. We are, therefore, entitled to reserve our judg- ment, both as to the value claimed for this vac- cination, and as to the true nature of the microbe cultivated by Ferran, and considered by him to be the infecting agent of cholera. If, again, we recur to the facts established by Bochefontaine, it may be asked whether subcutaneous injection is the true mode of inoculation applicable to this disease, and if the process adopted by Bochefontaine, of intro- THE MICROBES OF HUMAN DISEASES. 207 ducing the attenuated microbe into the stomach by means of pills or a liquid, would not be more rational. Mode of Propagation and Persistence of Cholera.— The upper part of the delta of the Ganges seems to be the original home of cholera and its microbe. Below this region, the stagnant water on each side of the river, infected with every species of ordure, renders the maritime base of the delta wholly unin- habitable. But even in its upper part the land is nearly covered by water. In order to build a house, the earth is heaped up to raise the level of the soil, and the house stands on the embankment, surrounded by water.