CHAPTER IX
DISINFECTION 322
APPENDIX 337
ILLUSTRATIONS
[Illustrations starred (*) are reproduced by permission of the Scientific Press from Drs. Spitta and Slater's _Atlas of Bacteriology_.]
PAGE
VARIOUS FORMS OF BACTERIA 9
SARCINA 10
NORMAL AND PLEOMORPHIC FORMS OF TUBERCLE 13
BACILLI, SHOWING FLAGELLA 15
VARIOUS FORMS OF SPORE FORMATION AND FLAGELLA 18
POTATO IN A ROUX TUBE PREPARED FOR CULTIVATION 22
STAPHYLOCOCCUS PYOGENES AUREUS INCUBATOR _to face_ 22
CULTURE MEDIA READY FOR INOCULATION 23
INOCULATING NEEDLES 24
PASTEUR'S LARGE INCUBATOR FOR CULTIVATION AT ROOM TEMPERATURE _to face_ 24
METHOD OF PRODUCING HYDROGEN BY KIPP'S APPARATUS FOR CULTIVATION OF ANAËROBES 27
ANAËROBIC CULTURE 28
KOCH'S STEAM STERILISER 31
LEVELLING APPARATUS FOR KOCH'S PLATE 40
MOIST CHAMBER IN WHICH KOCH'S PLATES ARE INCUBATED 41
HOT-AIR STERILISER 42
THE HANGING DROP 44
DRYING STAGE FOR FIXING FILMS 45
TYPES OF LIQUEFACTION OF GELATINE 47
WOLFHÜGEL'S COUNTER 49
PETRI'S DISH 50
BERKEFELD FILTER 52
APPARATUS FOR FILTERING WATER TO FACILITATE ITS BACTERIOLOGICAL EXAMINATION _to face_ 52
BACTERIA OF TYPHOID FEVER 56
BACILLUS COLI COMMUNIS 60
THE COMMA-SHAPED BACILLUS OF CHOLERA 66
*BACILLUS TYPHOSUS _to face_ 66
*BACILLUS TYPHOSUS " 66
*BACILLUS COLI COMMUNIS " 66
*BACILLUS MYCOIDES " 66
PASTEUR-CHAMBERLAND FILTER 80
PROTEUS VULGARIS 86
BACILLUS ENTERIDITIS SPOROGENES 86
A PLAN OF SEPTIC TANK AND FILTER-BEDS 91
FILTER-BEDS 94
MIQUEL'S FLASK 97
SEDGWICK'S SUGAR-TUBE 99
SEDGWICK'S TUBE 100
SACCHAROMYCES CEREVISIÆ 117
ASCOSPORE FORMATION 120
GYPSUM BLOCK 121
YEAST _to face_ 122
ASCOSPORE FORMATION IN YEAST " 122
NITROGEN-FIXING BACTERIA FROM ROOTLET NODULES " 122
*BACILLUS OF TETANUS " 122
SACCHAROMYCES ELLIPSOIDEUS 126
SACCHAROMYCES PASTORIANUS 126
BACILLUS ACIDI LACTICI 131
BACILLUS BUTYRICUS 133
KIPP'S APPARATUS 140
FRÄNKEL'S TUBE 141
BUCHNER'S TUBE 141
A METHOD OF GROWING CULTIVATIONS IN A VACUUM OVER PYROGALLIC SOLUTION 143
MICROCOCCUS FROM SOIL 151
NITROUS ORGANISM _to face_ 158
NITRIC ORGANISM " 158
NITROGEN-FIXING ORGANISM FROM SECRETION OF ROOT-NODULES " 158
ROOTLET OF PEA WITH NODULES 163
NITROGEN-FIXING BACTERIA IN SITU IN NODULE ON ROOTLET OF A PEA _to face_ 164
NITROGEN-FIXING BACTERIA IN SITU IN ROOTLET-NODULE OF A PEA " 164
NITROGEN-FIXING BACTERIA IN SITU IN ROOT-NODULE OF A PEA " 164
BACILLUS OF TETANUS 170
BACILLUS OF SYMPTOMATIC ANTHRAX 172
BACILLUS OF MALIGNANT ŒDEMA 172
A CENTRIFUGE 228
SUSPENDED SPINAL CORD 255
FLASK USED IN THE PREPARATION OF THE TOXIN OF DIPHTHERIA 262
*BACILLUS TUBERCULOSIS _to face_ 280
*BACILLUS TUBERCULOSIS " 280
*STREPTOCOCCUS PYOGENES " 280
*BACILLUS ANTHRACIS " 280
FLASK USED IN THE PREPARATION OF TUBERCULIN 282
BACILLUS OF DIPHTHERIA 289
TYPES OF STREPTOCOCCUS 298
MICROCOCCUS TETRAGONUS 299
DIPLOCOCCUS OF NEISSER 300
BACILLUS OF ANTHRAX AND BLOOD CORPUSCLES 302
THREADS OF BACILLUS ANTHRACIS, SHOWING SPORES 302
BACILLUS OF PLAGUE 306
*BACILLUS OF PLAGUE _to face_ 310
*BACILLUS OF LEPROSY " 310
STREPTOTHRIX ACTINOMYCES " 310
BACILLUS MALLEI " 310
DIPLOCOCCUS OF PNEUMONIA 312
BACILLUS OF INFLUENZA 315
INTRODUCTION
We live in a world that is teeming with life. From the earliest times of man that life has been studied and the observations recorded. Thus there has slowly come to be a considerable accumulation of knowledge concerning the various forms (morphology) and functions (physiology) of organised life. This we call the science of biology. It has for its object the study of organic beings, and for its end the knowledge of the laws of their organisation and activity. Slowly, too, in the midst of this gradual accumulation of facts, we begin to see incoherence becoming coherent, chaos becoming cosmos, chance and accident becoming law. Further, the contemplation and comprehension which built up the edifice of modern biology is assuming a new relationship to practical life. Biology can no longer be considered only as an academic occupation or as a theoretical pabulum upon which the leisured mind may ruminate. With rapid strides and determined face this giant of knowledge has marched into the arena of practical politics. The world is opening its eyes to a reality which it had mistaken for a vision.
This application of biology to life and its problems has in recent years been nowhere more marked than in the realm of bacteriology. This comparatively new science, associated with the great names of Pasteur, Koch, and Lister, furnishes indeed a stock illustration of the applicability of pure biology. Turn where we will, we shall find the work of the unseen hosts of bacteria daily claiming more and more attention from practical people. Thus biology, even when clothed in the form of microscopic cells, is coming to occupy a new place in the minds of men. "Its evolution," as Professor Patrick Geddes declares, "forms part of the general social evolution." Certainly its recent rapid development forms a remarkable feature in the practical science of our time. Not only in the diagnosis and treatment of disease, nor even in the various applications of preventive medicine, but in ever-increasing degree and sphere, micro-organisms are recognised as agents of utility or otherwise no longer to be ignored. They occur in our drinking water, in our milk supply, in the air we breathe. They ripen cream, and flavour butter. They purify sewage, and remove waste organic products from the land. They are the active agents in a dozen industrial fermentations. They assist in the fixation of free nitrogen, and they build up assimilable compounds. Their activity assumes innumerable phases and occupies many spheres, more frequently proving themselves beneficial than injurious. They are both economic and industrious in the best biological sense of the terms.
Yet bacteriology has its limitations. It is well to recognise this, for the new science has in some measure suffered in the past from over-zealous friends. It cannot achieve everything demanded of it, nor can it furnish a cause for every disease. It is a science fuller of hope than proved and tested knowledge. We are as yet only upon the threshold of the matter. As in the neighbouring realm of chemistry, it is to be feared that bacteriology has not been without its alchemy. The interpretations and conclusions which have been drawn from time to time respecting bacteriological work have led to alarmist views which have not, by later investigation, been fully supported. Again, the science has had devotees who have fondly believed, like the alchemists, that the twin secret of transmuting the baser metals into gold and of indefinitely prolonging human life was at last to be known. But neither the worst fears of the alarmist nor the most sanguine hopes of the alchemist have been verified. Science, fortunately, does not progress at such speed, or with such kindly accommodation. It holds many things in its hands, but not finally life or death. It has not yet brought to light either "the philosopher's stone" or "the vital essence."
What has already been said affords ample reason for a wider dissemination of the elementary facts of bacteriological science. But there are other reasons of a more practical nature. Municipalities are expending public moneys in water analysis, in the examination of milk, in the inspection of cows and dairies, in the bacterial treatment of sewage, and in disinfection and other branches of public health administration. Again, the newly formed National Association for the Prevention of Tuberculosis, our increasing colonial possessions with their tropical diseases, even medical science itself, which is year by year becoming more preventive, make an increasing claim upon public opinion. The successful accomplishment and solution of these questions depend in a measure upon an educated public opinion respecting the elements of bacteriology. Recently it was urged that "the first elements of bacteriology should be shadowed forth in the primary school."[1] This course was advised owing to such knowledge being of value to those engaged in dairying. As we shall point out at a later stage, many of the undesirable changes occurring in milk are due to bacteria, even as the success of the butter and cheese industries depends on the use and control of the fermentative processes due to their action. Much of the uncertainty attending the manufacture of dairy products can only be abolished by the careful application of some knowledge of the flora of milk. In Denmark and in Scandinavia the importance of such knowledge is realised and acted upon. America, too, has not been slow to respond to these needs; but in England comparatively little has been done in this direction.[2]
Whilst there can be no doubt as to the advantage of a wider dissemination of the ascertained facts concerning bacteria, it should be borne in mind that only patient, skilled observation and experimental research in well-equipped laboratories can advance this branch of science, or indeed train bacteriologists. The lives of Darwin and of Pasteur adequately illustrate this truth. Yet it is observable that States and public bodies are slow to act upon it, and frequently in the past the most useful and substantial support for the advancement of science has been forthcoming only from private sources. As the world learns its intimate relation to science and the interdependence between its life and scientific truth, it may be expected more heartily to support science.
BACTERIA