MR. PRESIDENT, LADIES AND Gentlemen-One of the first questions suggested by the subject assigned to me is: What diseases can be restricted or prevented? So far as relates to the class of diseases the answer is easy. The diseases which can be restricted are those which are communicable. The 'communicable diseases include those which are contagious, those which are infectious, those which are in any way communicated or spread from one person to another-such diseases as smallpox, scarlet fever, diphtheria, measles and whooping-cough.

Then an important question is, whether any of the most dangerous diseases which have not heretofore been considered communicable do really belong to that class, and can therefore be restricted or prevented. To this question we can now answer "yes." At least one of the most dangerous of all diseases, namely, consumption, has in recent years been found to be a communicable disease and a preventable disease. There is considerable evidence now tending to prove that pneumonia is a communicable disease, and that probably many deaths from that disease could be prevented by the general adoption of measures which recent investigations have revealed.

THE IMPORTANCE OF THIS SUBJECT.

The importance of the subject of the restriction of the dangerous diseases cannot easily be estimated. Let us see what aid the vital statistics can give

us.

The statistics of deaths in Michigan are not perfect, but the relative importance of the several diseases is probably shown with approximate accuracy. The diagram which I exhibit, and copies of which are distributed in

*An address before the Sanitary Convention, Charlevoix, Michigan, August 15th, 1890.

this audience, is accurately drawn to scale, and correctly represents the deaths. reported to the Secretary of the State. The diagram shows the relative importance of the several dangerous communicable diseases. It shows that in Michigan every one of the diseases named in the diagram is much more important than smallpox as a cause of death, and that when compared with diphtheria, and especially when compared with consumption, smallpox is insignificant, or at least that it was so during the twelve years 1876-87. If the diagram included pneumonia it would appear between "diphtheria" and "typhoid fever," and then the five diseases which cause most deaths in Michigan would be shown in the diagram. The five diseases which cause most deaths in Michigan, named in the order of their importance, are: Consumption, diphtheria, typhoid fever and scarlet fever.

We thus gain some idea of the vast importance of this subject—the restriction and prevention of the dangerous communicable diseases which include all the most important causes of deaths in Michigan. Especially do we appreciate the importance of this subject when we consider that we absolutely know that a large proportion of the cases and deaths from the most of these disease are preventable, and we believe that this is true of all of these diseases.

CO-OPERATION NECESSARY FOR THE RESTRICTION OF DISEASE.

For their prevention, however, it is necessary that all the people shall co-operate. No one can fully protect himself so long as others do not understand the subject and act accordingly. Therefore, the only way these most important causes of deaths can be most completely avoided by any of us, is by increasing the proportion of the people who know how to restrict and prevent them. If we except smallpox, which may, by vaccination, be avoided by each person for himself, this statement is true relative to each of the dangerous communicable diseases. For the restriction of each there is required general diffusion of knowledge, and general co-operation of all classes of people. That is a good reason why "the restriction and prevention of the dangerous diseases'' is given so prominent a place on the programme of every Sanitary Convention.

HOW THESE DISEASES ARE SPREAD.

But these diseases are not all spread in the same way; and it is necessary that the people generally shall know how each one is spread in order to know how to restrict each disease. In each disease something goes from a sick person which is capable of causing the disease. It goes from that part of the body in which the disease is located, and generally it thrives best when it reaches that same part of the body to which it goes. In consumption that part is generally the lungs; and the specific cause of consumption goes out with the sputa and is scattered about not only wherever the moist sputa goes, but also wherever the dust from the dried sputa goes. And as the dust of the air is breathed in with the air inhaled, there is opportunity for the specific cause of consumption to go at once to the part of the body in which it is usually found.

This indicates what is the most important measure for the restriction of consumption, namely, the destruction or disinfection of all sputa from every consumptive person.

But this subject will be sufficiently dealt with by the speakers who are to follow me.

TYPHOID FEVER.

Typhoid fever causes about ten times as many deaths in Michigan as smallpox does-probably about one thousand deaths per year-and most of these deaths should be prevented. The greatest number of deaths from typhoid fever is of persons in the prime of life, and this should prompt to greater efforts for the prevention of this disease.

The most common modes of spread of typhoid fever are not the same as of smallpox and consumption, consequently the measures for its restriction and prevention are not the same. The pamphlets on this subject issued by the State Board of Health, and freely distributed here, contain plain directions how to prevent typhoid fever, and how to restrict its spread. It is now believed that typhoid fever is most frequently spread by means of the drinking water, that the microscopic cause of the disease is probably reproduced in the bodies of persons who have the disease, and that this specific cause gains access to the drinking water by filtering through the soil, and sometimes by being washed into wells or streams from which the drinking water is drawn. The noted instance at Lausanne, Switzerland, where the discharges from typhoid fever patients were thrown into a small stream, which disappeared by sinking into the earth and gravel, and reappeared about a half mile distant as a mountain spring, the clear water of which caused typhoid fever in 144 persons, is instructive, and is useful for us to hold in mind as illustrative of how the disease may be spread. The most usual mode of spread is probably by way of the privy vault and the neighboring well. The facts concerning the outbreak at Lausanne prove (and the same has been indicated in other instances) that the cause of typhoid fever sometimes passes great distances by way of the underground water flowing through strata of gravel.

We must not forget, however, that typhoid fever may be spread through the air, that the supposed "germ" of the disease is not destroyed by simply freezing, and is not yet known to be destroyed by ordinary drying. We know that the microscopic "germ" of consumption is most dangerous when dried and floating in the air we breathe. It may be that the specific cause of typhoid fever is dangerous in the same way.

The prevention and restriction of typhoid fever requires the disinfection of all bowel discharges from those sick with such disease, and constant watchfulness of the sources of supply of water for drinking and culinary purposes. All water from a suspected source should be boiled before its use. Numerous instances are reported where typhoid fever has been spread by the rinsing of milk cans with water apparently pure, but really infected with the germs of typhoid fever, capable of infecting the milk. This teaches us the importance of having water free from typhoid infection for all household purposes.

Typhoid fever is a disease which, in my opinion, it is important that citizens of every village should understand, because of the nature of the soil and earth underlying villages and the surrounding country from which the milk supply comes. Sooner or later there will come a time when no ordinary well in such a place can be safely relied upon to supply water free from the specific cause of typhoid fever.

But the general water supply of cities and villages is a matter of the greatest concern, and it should be procured from places where there can be no probability of immediate or remote contamination. The well-known outbreak of typhoid fever at Plymouth, Pa., where over a thousand cases and 114 deaths occurred, is apparently an illustration of how great a calamity may follow the fouling of a general water supply by the specific cause of typhoid fever.

There is not time at my disposal to give all the evidence proving the enormous saving of human life from the ravages of typhoid fever which in recent years has been accomplished because of such knowledge as this to which I have just alluded, but I wish briefly to refer to some of this evidence. a pamphlet published by the Michigan State Board of Health, and entitled, "The Influence of Sewerage and Water Supply on the Death Rate in Cities," Mr. Erwin F. Smith shows conclusively very great reductions in the mortality from typhoid fever in many of the great cities in this country and in foreign countries, the reductions in the typhoid mortality following the introduction of systems of sewerage and general water supplies. For instance, in the city of Munich the death rate from typhoid fever in the period from 1854 to 1859 was 24.2 per ten thousand inhabitants, while in 1884 it had declined to 1.4 per ten thousand inhabitants; that is, before the city was sewered, and while it was supplied with water from wells, the mortality from typhoid fever was about seventeen times as great as it was after the city was well sewered and had a good general water supply.

To give you a mental image of this important subject, I have had copies. made of two diagrams prepared by Mr. Erwin F. Smith to illustrate his paper, and they are here for distribution to such of you as will study them.

If there should be in Michigan such a reduction of the mortality from typhoid fever as was secured in Munich through better sewerage and water supply, there would be a saving of over 900 lives per year and over 9,000 cases of sickness per year. To point out how such favorable conditions for healthful existence may be secured, is one of the objects of such sanitary conventions as this.

Let us pass now to the consideration of diseases which are fatal chiefly to children.

DIPHTHERIA.

About 85 per cent. of all the deaths from diphtheria are of children under 10 years of age. Grown people have diphtheria, but it is usually considered only as an ordinary sore throat, and proper precautions to prevent the spread