pathogenic bacteria, is absurd and opposed to the experience of all scientists who have carefully studied the laws of heredity, crossing and variation. The influence of heredity as a predisposing cause of disease has always been recognized, and cannot be disregarded. The enthusiastic baceriologist who has carefully read and reflected upon Darwin's works, especially "The Origin of Species," and "Animals and Plants Under Domestication," or the celebrated work of Professor Lucas, "Natural Heredity," will no longer hold to the opinion that all diseases are caused by microbes.

Bacteria alone cannot cause disease. There must of necessity be due coöperation of both factors, heredity and microbic activity. At first Koch put forth the opinion that bacilli are the real producers of disease; but he has since greatly modified his views, and as he states, to maintain such a view it must be shown: (1) That bacilli are capable of producing disease. (2) That this ability to do so is constant. (3) That pathogenic bacteria produce the same sort of disease in all animals irrespective of species. (4) That they cause infectious diseases of a typic, distinctly marked and sharply defined course. Cohn divided bacteria into three classes, pathogenic, zymogenic and chromagenic. As regards the first condition, it has been proved that the bacillus of consumption can produce a brown pigment upon potato and cause acid fermentation in a solution of sugar. It is therefore pathogenic, zymogenic and chromagenic. It has also been shown that the cholera bacillus can produce yellow or brown pigment upon potato and cause acid fermentation in solutions of sugar; that the so-called golden-pus bacteria form a splendid yellow pigment upon potato or in cultures and in solutions of sugar produce acid. From such facts it is clear that specificity depends upon the nature of the nutrient media, and that bacteria can only draw out or make manifest that which is already performed in the medium structure. Furthermore, we see that they are capable of acting indifferently as pathogenic, zymogenic and chromagenic bacteria.

As regards the second condition. From the date of Pasteur's discovery to the present time modifications of bacteria have been brought about in such a way that they no longer produce poisonous effects on the organism but behave like harmless saprophytes. The results obtained by immunization amply prove the facts.

The third condition requires that special pathogenic bacilli produce the same form of disease in all animals without regard to species. Is such the case? It is not. For instance, some disease germs only affect certain hosts; thus: syphilis, leprosy, cholera and typhoid fever are peculiar to mankind, while tuberculosis, glanders and anthrax attack both man and certain kinds of animals. Negroes are easily affected by smallpox, white men by yellow fever, and so on.

Finally, does a specific disease germ cause only one kind of disease, as postulated by the fourth condition? Again the reply is in the negative. Formation of nodules in the connective tissues may be brought about by the germs of syphilis, leprosy, glanders and tuberculosis.

Suppuration may be caused by the germs of syphilis, erysipelas, tuberculosis, anthrax, typhoid and pneumonia. The common colon bacillus and bacterium of cholera can cause diarrhea, thus showing that one and the same morbid effect can be produced by several distinct species of bacteria. Moreover, one and the same specific germ can cause different morbid phenomena. Thus diphtheria bacilli can cause diphtheria, paralysis, or acute blood poisoning; the bacterium of erysipelas can produce erysipelas in the skin and inflammation or suppuration in the lungs; pneumococci may cause pneumonia, blood-poisoning and inflammation of the brain; tubercle bacilli cause the formation of tubercle in connective tissues, suppuration in the lungs, true consumption, cerebral inflammation, and diseased processes in bones. Such facts show that the effects of bacteria upon living or dead tissue or organisms are modified according to the nature of the environment in which they exercise their peculiar powers.

Since all hereditary taints, traits and peculiarities are prepared for transmission in the uterus or ovaries, so to speak, it seems natural to conclude that the female holds controlling power over the offspring, and from conception to birth is in a position to reproduce her own kind but slightly changed, thus manifesting a tendency to retain and transmit hereditary peculiarities, by which permanence of the species is insured; while the male element, less limited in its activities, has a strong tendency to vary, in this way endangering the preservation of the species. The germ cell is receptive, conservative, has little tendency to variation, and transmits faithfully from one generation to another such diseases or morbid tendencies as have stamped their impress upon the fertilized ovum. The sperm cell, on the contrary, is strongly inclined to variation, is progressive, and by its natural impulse toward change tends to eliminate heredity and annihilate species.

The fact that certain diseases appear to have changed within half a century, that new forms of disease processes are said to have appeared, may be due to those progressive attributes of sperm cells; while the pertinacity with which certain diseases appear to retain their typicly defined course of manifestation, without change or variation, may be due to the conservative nature of germ cells. It may be that after conjugation, the sperm and germ cells pursue each an independent course of development; thus impressing upon the offspring traits and morbid tendencies from both parents. I am not disposed to accept this view of the case, but would rather favor cooperation or a harmonious working together of the two elements, for the production of an organism in which some points from both parents are transmitted, some neutralized or eliminated by the union and some modified, the resulting organism being, as it were, a mean between the two influences; or, as Huxley has so clearly expressed it, "Every animal is the resultant of two tendencies, the one morphologic, the other physiologic," to which let me add, one tendency conservative, serving to preserve immutability of species; the other pro

gressive, inclined to variation, and destructive of constancy in organic forms.

In this paper I have grouped together some facts to show that in all animals and plants there exists a double tendency-one toward variation and consequent elimination of permanent forms and traits, and one toward conservatism or immutability of species; that the latter is known as heredity, the former as variation; that these tendencies apply equally to diseases; that they may be dormant in the system for several generations, to appear in some descendant more or less remote; that certain attributes, special developments, and developments common to both sexes, diseases common to both sexes, and certain functions may be arrested by development of functions peculiar to each sex; that these may reappear in the offspring, or may be reawakened when the functions whose development had arrested their growth have discontinued their activities; that diseases following developments of structure caused by increased functional activity are as readily transmitted as such increased structural developments; that bacteriology is concerned with environment; that bacteria cannot be the sole producers of disease; and finally, that heredity and bacteriology are mutually dependant upon each other and must coöperate if they are to become active in the production of disease.

THE CLIMATOLOGIC TREATMENT OF TUBERCULOSIS.* BY ETHAN H. SMITH, M. D., SANTA CLARA, CALIFORNIA.

THIS subject is so broad, offers so many chances for digression, and is sc little classified that it is difficult to write a systematic paper thereon. The contents of this paper will consist principally of a summary of observations made while journeying through the country mentioned or residing therein. I shall avoid speaking in detail of places I have not seen.

The climatic, topographic and latitudinal or longitudinal conditions necessary to produce an ideal climate have never as yet been realized. No matter what we read or hear of a place, no matter how beautiful it may appear on a chance visit, there is always something more or less to act as a drawback when we learn all about it. An equable climate in a temperate zone, free from oppressive moisture, not an absolute desert, not too hot and never cold, is the phantom which. we as climatologists have been seeking during past years. We must stop seeking for the impossible and study how to make the home climate as enduring as possible for such patients as cannot or will not seek another clime. I believe that we have overlooked this side of the matter almost completely. We dose our patient, disinfect and asepticize his indoor surroundings, but pay little attention to the possibility of utilizing our own outdoor atmosphere to combat the disease. It is too near by. We are too familiar with it to hold it above contempt. Plenty of individual means gives opportunity to make any

*Read before the ANN ARBOR MEDICAL CLUB.

Plenty of public

ordinary good climate available to the individual. funds will ameliorate climatic faults for the improvident and the pauper. To stamp out tuberculosis among the two latter classes is to destroy one of the chief breeding grounds. The wealthy man who gives to such an enterprise is making a selfish gift, for he is protecting his own from contamination.

In sending people away to try the benefits of climate, it is highly essential that they should have sufficient money to pay for ordinary comforts. Some must have luxuries in addition. Comparatively few individuals have the means to try a change of climate in a way to receive benefit. In time much of this difficulty will be obviated by public aid. Too many times a recommendation to try change of climate is prompted by the undesirability of the case. It is an easy way to rid oneself of an exasperating patient, or family, or to avoid a possible homeopathic or osteopathic complication. The recommendation to change climate is based more on empiricism than on scientific and accurate knowledge.

Localities gain repute as beneficial places for tuberculous patients by chance. While in the beginning they may be beneficial, they ultimately become places of pestilence from overcrowding. I believe it is a good thing to separate a tuberculous patient from an environment saturated with the germs of that disease. While the outdoor conditions of some newly-found place may be unfavorable to the development of the tubercle bacilli, the building of houses and the using of modern methods and means to accommodate guests, soon create a favorable lodgement for the bacilli. Crowd such a habitation with tuberculous patients and they are in a worse situation than in their own homes. So long as there were no houses and the patient lived in a wagon or tent, the climate proved beneficial. Stringent measures should be adopted to prevent more than a given number of individuals from being domiciled at one time in any establishment of known capacity. I believe that in all climates where the temperature will permit, the patient should live in a tent and sleep in a comfortable cot with warm mattress. If the weather is inclement, he still has abundance of fresh air and his progress is not hindered by reason of being indoors.

Before sending a patient away there are certain matters to be considered. Does the physician know anything about the place he proposes to recommend? Is it a high or low altitude? Will the season of the year be suitable at the time the patient arrives there? Will the patient be content and happy, or will he fret and become worse through homesickness? Can the patient have comfortable and safe accommodation when he arrives? Change of climate often makes strong and well people temporarily ill. Has the patient any complicating illness or leision which will not tolerate the new climate? By what route must the patient go? Can he avoid dangerously high altitudes in making the journey. Taken all in all, the climatic problem is complicated and difficult to solve.

Early last summer a society of climatologists made a tour of the

Southwest and the Pacific coast. The management of each sanitarium, representatives of cities and towns, real estate speculators and transportation companies along their route combined to make them have just as good a time as possible. The best of everything was paraded before them. The route through their stomachs was not overlooked. They saw the country at the most favorable time of the year, although they were perhaps informed that the weather, food, and drink were very mediocre. as compared with midwinter. I would not give much for the deductions of that association. They received an exaggerated and extravagant idea of everything. Medical men should travel singly or in pairs at most and unheralded, if they would observe things as they are. They should use their own minds and pay small heed to what they are told until they verify the statements by careful investigation.

I will consider that part of the country west of the Mississippi river.

Montana and Idaho are too far north and are not much sought after, although there are places which have proved of great benefit to persons electing them at a proper season of the year and recuperating sufficiently to be able to withstand the rigors of winter.

Colorado was a Mecca for a long time. The altitude of most Colorado resorts is too high for many patients. The winters are very severe, thus keeping patients shut in the house much of the time, and pneumonia is prevalent even among the robust inhabitants. At times the outside air is full of frost needles and dangerous for anybody to breathe. In summer a iimited proportion of tuberculous patients may thrive there. As it is now many miserable, coughing individuals are frequently shut in a crowded hotel or boarding-house for days at a time, and in an atmosphere laden with the morbid products of tuberculosis. Such climatic imbecility as that results in many deaths.

New Mexico and Arizona are so similar that I can speak of them together. The country is made up of desert plains, broken by low, barren mountain ranges. An occasional patch of cultivated land greets the eye where irrigation is a limited possibility. In summer the heat is so intense, the dust so excessive, sand storms so frequent, that many business men send their families to a more desirable locality. Many persons cannot endure the climate. Malaria is prevalent. The railroads find it difficult to keep a supply of telegraph operators and agents. Mexicans thrive here because it is their native climate. We hear of ranch life in New Mexico and Arizona and associate it with green fields, running water, and growing crops. A cattle ranch comprises many thousands of acres of desert, sparsely covered with sage brush, grease wood, cactus and mesquite bushes. The latter afford the food for the cattle. A steer must range over acres to secure food for one day and must travel miles to obtain water. Life here for many months in the year is a hardship except in the few isolated places. where an enormous outlay of capital has made it endurable with only a small degree of comfort. These places are very expensive. The sur