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 o^o)^ ^ "^ » 
 
 INTRODUCTORY LECTURE ON HYGIENE, PUBLIC 
 HEALTH AND PREVENTIVE MEDICINE. 
 
 BY 
 
 EGBERT CEAIK, M.P., LL.D., ' 
 Dean of the Faculty of Medicine, Professor of Hygiene, McGill University. 
 
 Reprinted from the Montreal Medical Journal, November, 1896. 
 
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 INTRODUCTORY LECTURE 
 
 ON 
 
 HYGIENE, PUBLIC HEALTH AND PREVENTIVE MEDICINE. 
 
 BY 
 
 Robert Craik, M.D., LL.D., 
 Dean of the Faculty of Medicine, Professor of Hygiene, McGill University. 
 
 In beginning the study of a new subject, it is always well to obtain 
 as clear a view as possible of the field which is to be explored and 
 cultivated ; its scope, its limitations, its possibilities and the nature of 
 the work which is to be performed in it ; and the more clearly these 
 are understood at the beginning, the more intelligently and success- 
 fully will the work be carried on. 
 
 In entering, therefore, upon our )'eorganized course of Hygiene, I 
 have thought it well to devote a short lecture to a survey of the 
 ground to be covered, and an outline of the manner in which we pro- 
 pose to utilize it. 
 
 It is impossible in a single word or sentence to define what Hygiene 
 is, or what are its scope and its limitations. The word itself means 
 health, or things pertaining to health, being derived from the name 
 of the Greek Goddess of Health, Hygeia, and in its widest sense, 
 therefore the study of Hygiene means the study of all things pertain- 
 ing to health, whether beneficial or detrimental. This, of course, 
 includes the study of Disease, which is strictly a department of 
 Hygiene on account of the effect which disease has upon health. But 
 the Science of Medicine has long since chimed as its own particular 
 province, the study of Disea.se, and Hygiene has been glad lai'gely to 
 concede the claim, having still an ample territory over which there 
 can be no dispute. But there is also a large area which is common 
 to both, and over which neither can claim exclusive jurisdiction. 
 
Health and Disease may be looked upon as the antithesis of each 
 other, having much the same relations as light and darkness, pleasure 
 and pain, good and evil. But opposite as these things may seem to be, 
 we cannot in our minds disassociate them, for light would scarcely be 
 realized as light if we were ignorant of darkness, pleasure would 
 scarcely be so enjoyable if we had never felt pain, and we could 
 scarcely fix a standard of health, if it were not possible to contrast 
 it with disease. 
 
 In this way the study of Medicine and the study of Hygiene meet 
 and overlap each other, the one cannot properly be understood with- 
 out some knowledge of the other ; the Physician in studying Disease 
 fixes his attention upon those points in which it differs from Health, 
 while the Hygienist, in adjusting his standard of Health, must be able 
 to recognize the signs and symptoms which indicate Disease. 
 
 This common ground of study between the Physician and the 
 Hygienist or Sanitarian, instead of producing antag(<nism or diver- 
 gence, really binds them together, the studies of the one passing 
 imperceptiblj' into those of the other, so that every Physician becomes 
 more or less a Hygienist, and nearly every Hygienist becomes, or at 
 least qualifies himself to be a Physician. Both are working to rid 
 the world as much as possible of Disease, but while the Science of 
 Medicine aims l)oth at the prevention and cure of Disease, the Science 
 of Hygiene occupies itself almost wholly with its prevention ; and 
 inasmuch as prevention is always better than cure. Hygiene as a part 
 of Medicine is assisting in the noblest part of its work. 
 
 It may be said therefore, that the peculiar province of Hygiene is, — 
 the study and practice of all those means that tend to preserve and to 
 improve health, and to prevent disease. 
 
 In its most comprehensive sense it includes all livi ig things, but in 
 its usual restricted sense it applies more particulai'ly to the human 
 race, with its subdivisions into states or nations, provinces, communi- 
 ties, families and individuals ; a conmion sub-division of the subject 
 being into : (</.) private or individual Hygiene ; (b) public Hygiene and 
 (<;) international Hygiene. 
 
 In its highest sense also, Hygiene concerns itself not only with the 
 physical health of individuals and communities, but also with their 
 mental, moral and even their political health. 
 
 We have seen that the functions of the sanitarian and of the phy- 
 sician, though having much in common, differ chiefly in that the one 
 studies health and endeavours to preserve it, while the other studies 
 disease and endeavours to cure it, and their relative spheres of action 
 seem tolerably well defined. 
 
But though in the abstract, health and disease seem to be ahnost 
 the opposite of each other, in practice they are found often to shade 
 ahnost insensibly into each other, making it difficult to tell where the 
 one ends and the other begins, and making it impossible to give an 
 exact scientific definition of either of them. Perhaps the simplest 
 definitions are, — that health means that condition in which all the func- 
 tions are performed naturally, while disease means a condition in 
 which at least jome of the functions are more or less unnatural. In 
 these definitions, of course the whole ditference turns upon what is to 
 be understood as natural or unnatnral.and how are we to decide as to 
 what is natural ? 
 
 We shall probably find the nearest approach to it in the average 
 course of existence of indivduals in a prosperous coirnnunity. They 
 spring from a healthy parentage ; they are born at full time ; they 
 grow to healthy maturity ; they produce healthy oft-spring ; they 
 gradually fade and wither ; they die peacefully and return harmlessly 
 to dust. 
 
 But disease may alter all this ; parentage may be unwholesome or 
 depraved ; birth may be difficult or untimely : growth may be irregu- 
 lar or stunted ; progeny may be misshapen or fetible, or may be want- 
 '.ng altogether ; age may be laden with infirmities ; death may come 
 at any cime in a virulent and painful form ; and even the lifeless clay 
 by reason of its virulence may spread pestilence and death among 
 thousrnds of innocent victims. How difiei-ent the pictures. Health 
 represents peace, happiness and prosperity ; — disease represents grief, 
 misery and disaster. 
 
 What nobler woi'k, then, than to strive to blot out the lattei', and 
 to develop the former to still gi'eater excellence ? 
 
 But, it may be asked, how far is it possible to externunate disease 
 and to replace it by health and .soundness. Theoretically it ought to 
 be possible to exterminate disease, inasmuch as it is an unnatural con- 
 dition, and by strict obedience to natural laws, it ought to Ije made to 
 disappeai'. But natural laws, like all other laws, are constantly 
 broken ; and indeed anything like perfect obedience to them is scarcely 
 to be expected. They are often imperfectly understooiJ, and when 
 understood they are often beyond tnir control, and ordy a partial suc- 
 cess in onr work can therefore ever be looked for. 
 
 But though we can never hope to completely ei'adicate all diseases, 
 we may confidently expect to exterminate a large number of them, 
 and to so hiodify and control a still greater number, as to render 
 them comparatively harudess, thus i-educing the sum total of misery 
 and mortality in a very important degree. In proof of this we have 
 
e 
 
 only to think of what vaccination has done for smallpox, what anti- 
 toxin is now doino' for (li})hthf)'ia, what improved sanitary measures 
 have done for typhus fever, for scurvy, and for preventing the spread 
 of cliolera and other epidemics ; and in Sanitary Science, as in the 
 other Sciences, it seems impossible to limit the extent to which pro- 
 gress and improvement are to be carried. 
 
 A)id how have these successes lieen achieved ? By carefully study- 
 ing the laws of Health and the natural (or unnatural) history of 
 Disease, and by appl} ing for their eluci<lation the modern methods of 
 scientific investifjation. 
 
 Physiology teaches that in an ideal state of health, in adult life, 
 the metabolism of the; tissues and oi'gans is perfect : that the pro- 
 cesses of waste and rr'generation exactlv balance each other, and that 
 to maintain this balance, the ingesta and (sxcreta must be in corres- 
 ponding proportion. Were it possible in a healthy body, and with 
 pure materials, always to maintain this ('(|uality, it would seem that 
 the process should go on indefinitely, and that something approaching 
 immortality should I'esult ; but with our earthly environment no such 
 perfection is possiltle ; under the most favou 'able circumstances the 
 metabolism is only approximately perfect, the materials are only 
 approximately pure, and almost from the beginning, a process of 
 gradual deterioration connnence.s, which, aided by other influences, 
 ultimately ends in djgenei'ation and death, and this without the 
 supervention of what can properly be called Disease, but only as the 
 result of proce.s,ses rendered imperfect by complex <listurbing forces 
 which pervade our whole surroundings. 
 
 As I have said, this process is not Disease. There is nothing un- 
 natural about it ; it is common to all living things with which vve ai'e 
 acquainted, and when it ends in the usual way, we .say death has 
 resulted from natural causes oi' from natural decay ; indeed we are 
 constrained to accept this result as the nearest approach to perfect 
 Health which is attainal>le in this world. It is in short the natural 
 or normal condition of all earthly living things. 
 
 If then we are to accept this as our type of Health, what is Disease 
 supposed to be ? It must at least l.)e something appreciably different, 
 either in degree or in quality ; something added, something taken away, 
 or something altered and perverted. A change sufficient to convert 
 a natural or normal process into one which is measurably unnatural 
 or abnormal. 
 
 It is the function of the Sanitarian by all means in his power to 
 prevent these changes. When the changes have occurred it becomes 
 the function of the physician to endeavour to remf)ve or counteract 
 them and restore the processes to their natural or normal condition. 
 
 
 t 
 

 M 
 
 But to be in a position to prevent Disease, the Sanitarian nnist 
 endeavour to ascertain its eauses, and the iiianni'r in wliieli tlii'si 
 causes react upon tin; organism in proiluciiii; Disease, 
 
 As Health is depemlent upon the uiaintenanee of a proper liuhince 
 between all the functions, and an ade{|uate supply of ])uit> n;aterials 
 to repair the constant waste, and maintain the hi-althy integrity of 
 the tissues an<l organs, we naturally loi)l< for the causes of ])isease 
 among those circumstances likely to disturb this balance, nr to vitiate 
 or destroy thi.-. healthy integrity of structure. 
 
 The causes of Disease, however varied and numerous, may virtually 
 all be said to act b}- interfering with or vitiating healthy nu- 
 trition. Most of them are connected with the ingesta and find 
 entry to the system along with them, being either normal ingredients in 
 improper proportion, or foreign substances abnormally mingled with 
 them. Such cau.ses are to be met with in the air we brcathf, in the food 
 we eat, and in the fluids we drink. Certain otln'i* active causes Hml 
 entrance tlu'ough wounds or abrasions, and still other causes and 
 influences react upon the Ijody from without, such as changes of tem- 
 perature or of atmo.spherie pressure, physical and mental exhaustion, Sic. 
 
 Among all the.se cau.ses of Di.sease none have of late years attracted 
 so much attention as those connected with the .so-called (!erm Theory. 
 The class of Infectious or Zymotic Diseases, with others analogous to 
 them, having been shown to depend upon speciHc organisms or gei-ms 
 for their origin and propagation, the study of these organisms in all 
 their relations to disease has distinctly been brought within the pro- 
 vince of Sanitary Science. 
 
 The constantly improving processes oH. Chemical and Phj^sical re- 
 seai'ch are also being daily brought more and more into the work of 
 Sanitary investigation, more jiarticularly with reference to air and 
 ventilation, water and'other beverages, and food with its adulterations. 
 In like manner some knowledw of Architecture ami Enjiineerinjf, as 
 applied not only to private dwellings, but to hospitals, .schools, ])ri.sons 
 and other public buildings, as well as to systems of drainage and 
 other matters, is every day becoming more impei-ative. 
 
 There are many other directions in which Sanitary Science is 
 extending its boundaries, and the area over which it is e> ercising 
 control is daily widening in all matters in which the health of indivi- 
 duals and communities is concerned. 
 
 The hitherto prevailing system of the Uniflcation of .Sanitary 
 Science is therefore no longer aile{]uate to its requirements. No 
 single teacher, however versatile and accomplished, can longer hope 
 to do even moderate justice to so extensive a subject ; but thanks to 
 the generous endowment of this Department by our Chancellor, Sir 
 
Donald A. Smith, we are at last alile to extend the scope of its 
 teachinjr in a degree conunensurate witli its importance, and to give 
 to it that Composite cliaracter which the diversity of its interests 
 deniantls. We have heen ahle tr) secure for Hygiene the active co- 
 operation of workers in other Departments of the Faculty. Dr. 
 Ruttan, Professor of Practical C'hemistry, who has been associated 
 with me for several years, will still further extend the work in Sani- 
 tary Chemistry and Physics, more particularly in connection with 
 water, soil, food and air ; while Dr. Adami, Professor of Pathology, 
 and Dr. Wyatt Jcjhnston, Lecturer in Bacteriology and Medico-Legal 
 Pathology, will contribute a very complete course of instruction in 
 Bacteriology in its relations with Preventive Medicine. This part of 
 the course will include the Biology (jf the Bacteria, methods of culture, 
 staining and sterilization, liacteriological examination of water, air, 
 soil and animal fluids and secretions, antisepsis of wounds. Serum 
 Therapy, Epidemiology, disinfection, quarantine, &c. 
 
 Ample means of illustration, with Microscopic and Laboratory 
 facilities wi'l be available in every part of the course ; and to make the 
 means of illustration still more effective, an extensive working museum 
 of models, specimens, diagrams and Sanitai-y apparatus of every kind 
 is being prepared, and will add greatly to the efficiency of the course. 
 
 It is hopetl also that a portion of the Lectures on Architecture and 
 Engineering in the Faculty of Applied Science may, by suitable 
 reciprocal arrangements, soon be made available for students in 
 Hj'giene. 
 
 In thus expanding the course and providing for additional study in 
 many directions, care has been taken in the interest of the students^ 
 not unnecessarily nor unduly to increase their labour; for much of the 
 additional work will be utilized in other Departments, chiefly in 
 Pathology and Practical Chemistry, so that unnecessary repetition 
 and duplication may be avoided. 
 
 The course of Hygiene, Public Health, and Preventive Medicine as 
 thus remodelled and extended, will henceforth take rank as a full 
 course, becoming one of the most prominent of the third year, a position 
 to which it is fully entitled by its constantly increasing importance. 
 
 In concluding this short address, let me remind you, that we do 
 not expect, even with our extended course and facilities, to make you 
 expert Specialists in Sanitary Science, or to qualify you without 
 further preparation to undertake the duties of Public Officers of 
 Health ; but we do expect of you that you will acquire a good knowl- 
 edge of the principles of the Science, and a sufiicient knowledge of its 
 details, to become intelligent critics and safe advisers in all matters 
 connected with Sanitary work. ' •' 
 
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