national vitality even more than on the resources of the minerals, lands, forests and waters. The average length of human life in different countries varies from less than 25 to more than 50 years. This span of life is increasing wherever sanitary science and preventive medicine are applied. It may be greatly extended. Our annual mortality from tuberculosis is about 150,000. Stopping three-fourths of the loss of life from this cause and from typhoid and other prevalent diseases would increase our average length of life fifteen years. There are constantly about 3,000,000 persons seriously ill in the United States, of whom 500,000 are consumptives. More than half this illness is preventable. If we count the value of each life lost at only $1,700, and reckon the average earning lost by illness at $700 a year for grown men, we find that the economic gain from mitigation of preventable disease in the United States would exceed $1,500,000,000 a year. This gain, or the lengthening and strengthening of life which it measures, can be had through medical investigation and practice, school and factory hygiene, restriction of labor by women and children, the education of the people in both public and private hygiene, and through improving the efficiency of our health service, municipal, State and national."

Dr. G. Lloyd Magruder said that the paper would be of infinite value both to this city and to the whole country. He hoped that the Society would be actively interested in the crusade for a pure milk supply, the importance of which had been so clearly pointed out in the paper; the necessity for it is very great, from the standpoint of prevention of typhoid, tuberculosis and diarrheal diseases. The local conditions with respect to the milk supply of Washington had been graphically described in the report of the Health Officer, also in Bulletin 41, Department of Agriculture. To bad local conditions must be added certain natural and customary conditions which make the dangers of impure milk greater than elsewhere: for instance, in European cities all the milk is heated before being used and thus is purified; in Northern cities in this country the climate is colder and thus the transportation temperature is more easily kept low to the advantage of the milk. Neither of these favorable factors prevails in Washington and other Southern cities. It is very unfortunate that there is in Washington no bacterial standard to which milk supplied to the public must conform; but the influence of the crusade in other directions has made itself felt in an improvement in the average bacterial content in milk sold in this city.

The

advice formulated and distributed by the Washington milk commission did much good in informing the consumers and making producers more careful; this sort of work should be continued until adequate legislative control can be instituted.

The danger of impure water supplies on dairy farms had not been recognized nor demonstrated until, in 1906, Dr. Magruder had secured the coöperation of the Department of Agriculture in the investigation of the question, and had clearly demonstrated the connection between dangerous water on the farm and dangerous milk in the city.

Dr. McPherson said that it was gratifying to know of multiplied and successful efforts to improve the public milk and water supplies; his own particular inclination was to attack a civic nuisance nearer home and more easily abated, viz: the urban chicken yard. It seemed strange to him that flocks of chickens. are allowed to be kept in small yards in congested parts of the city, where their droppings and coops are excellent breeding places for flies, and where the garbage upon which they are so often fed is left half consumed to putrefy and saturate the air with unwholesome exhalations. This feature of the "shady side of Washington" seemed to him to be in urgent need of correction, and he had been endeavoring for a number of years, unsuccessfully and with much disagreeable notoriety, to secure legislation for the control of this evil.

Dr. Kinyoun congratulated Dr. Kober upon his very comprehensive review of late progress in sanitary science. Dr. Kinyoun had nothing to add except with respect to certain local conditions. The prevalence of typhoid fever in the District had always been a problem of great interest to him. A number of years ago the influence of public water supplies upon the prevalence of typhoid fever had impressed him, and he had for two years studied the water supplied to this city; after investigation for one year he had become convinced that Potomac water was a menace to the public health, and he had aided to his fullest ability the efforts which finally secured the construction of the filtration plant. With the filter in full operation typhoid fever still exists in this city in very uncomfortable proportions, and it is evident that the problem is not solved. In his report made at the time he was investigating the water supply, he had made the following statement: The treatment of Potomac water is a problem of itself, and requires a separate solution. His opinion was that the solution lay in sedimentation before filtration. The abundant content of silt in Potomac water at times would inevitably interfere with the proper working of the filter beds, and he had accordingly. recommended the construction of adequate sedimentation basins. Such basins had never been provided. Now, while he did not believe that the water supply is responsible for all the typhoid occurring at this time, still it is true that on occasions colon

bacilli exist in the city water in uncomfortably large numbers. The rapid deposit of silt on the filter beds requires the frequent cleaning of them; after cleaning it is well known that sand filters are for a day or two ineffective and that the water is passed through practically raw. The mains are thus periodically filled with unpurified water, and the city is periodically left unprotected. Without the necessary basins for sedimentation, at times of great turbidity these breaks in efficiency are bound to occur, and their occurrence in no way reflects on the character of the filter plant nor on the way in which it is operated.

Dr. Chappell said that one of the charts exhibited by Dr. Kober seemed to carry conviction that pure water supplies reduce the prevalence of typhoid fever; it seemed to Dr. Chappell, however, that in order to carry conviction, it must be shown that no other causes have been operative to produce the same result. The experience of the City of Washington shows that some other causes than the water are at work here to spread typhoid fever; we are told that the house fly and the milk supply are at fault. But to conclude thus, the milk and the house fly must be exculpated in other cities, where the typhoid prevalence has been reduced by purifying the water. For accurate statistical purposes there should be comparative statements for all causes.

Dr. S. S. Adams said that we were given good water after the Potomac water had sent several Congressmen to their several rewards; he supposed that when the milk supplied the city gives enough trouble to Congressmen we will have remedial legislation. with respect to that commodity. He agreed in the main with what Dr. Kober had said, but not in toto. For instance, Dr. Adams has had more trouble with infants fed upon milk pasteurized in a wholesale fashion by the dealers than he has had with infants fed upon raw milk. Milk pasteurized in bulk by the distributor deteriorates more rapidly than raw milk and gives a false sense of security to the consumer.

He did not believe that the mortality rate of typhoid fever had been reduced by improving the water supply; the morbidity rate had been undoubtedly lowered and the number of deaths had, of course, decreased, but the rate of mortality owes its improvement to improved methods of treatment.

Dr. Atkinson said that he regretted that there was so much talk about our pure water supply when, after all, the water is not pure. It seemed to him preposterous to spend so much money on the purification of water, when the source of the raw material was such a filthy mud hole. There is pure water somewhere; why could it not be obtained for Washington? The pure mountain springs can be reached; it would be no impossible thing to pipe the water from them to the city; it seemed to him that in spite of the gigantic character of the undertaking it would be worth while.

Dr. Borden asked Dr. Kober if he had formed any opinion as to why the death rate of typhoid fever in Japan is so very low. Did racial immunity play a part in the production of this result? The question has not been well worked out.

In the Philippine Islands typhoid fever is not very prevalent. Two facts are suggestive: little milk is used there, and there are few flies-the larvae of the flies being destroyed by an ant peculiar to the islands.

In the Japanese-Russian war the typhoid figures were low, both as to incidence and mortality; at the same time the conditions for the spread of the disease were prominent. Some protection by racial immunity suggested itself strongly. In Japan there is no protection of public water supplies; the inference he would draw being that the race is not susceptible, rather than that contaminated water has no influence on the spread of the disease.

Dr. E. L. Morgan made a few remarks which the Secretary was unable to catch for record.

Dr. Kober in closing said that he believed Dr. Borden was correct in attributing the low typhoid figures in Japan to racial immunity rather than to sanitary precautions; one reason for this belief is that under like conditions no such statistics obtain in any other country.

To Dr. Adams he replied with the query: If improved methods of treatment are responsible for the improved death rate, why should his statistical chart show such sudden changes, as for instance, an improvement of 70 per cent. in the death rate of Cincinnati in two years? And why should improved methods of treatment, improved water supply and diminished death rate be synchronous?

The water-borne character of typhoid fever has been so well demonstrated that the etiological rôle of the house fly has been shown to be operative in only about 15 per cent. of the cases. So far as the milk-borne cases are concerned, the majority are after all water-borne, because the milk becomes contaminated most often by means of infected rinse water or water added for dilution. As regards the water supply of this city, the use of a coagulant or mechanical filtration was urged during the agitation for the establishment of a filtration plant, and since then the necessity of such treatment for part of the time has become appaPeriods of increased turbidity do have a distinct influence upon the bacterial efficiency of the sand filters, and preliminary sedimentation by gravity or the use of a coagulant at such times would serve to keep the sand filters at a maximum and uniform efficiency.

Dr. McPherson's suggestions as to the influence of the practice of keeping poultry in city yards upon the health of the community were important; such a practice could have no sanction.

from sanitary science. This particular feature of urban life entered into the whole question of dirty back yards-a problem which was of considerable gravity and should be solved.

THE LIFE OF THOMAS SYDENHAM, M. D.,
1624-1689.*

BY JOHN BENJAMIN NICHOLS, M. D.,

Washington, D. C.

Thomas Sydenham, who lived in England 1624-1689, has the reputation of having been one of the greatest physicians of all time, and of having exerted an epochal influence in the development of medical science.

Sydenham lived in a propitious age for great minds, the time when in England the Renaissance was in full swing, in science, religion and government. Mankind had just awakened from the intellectual torpor that had prevailed throughout the Middle Ages and had cast off the shackles of ecclesiastical domination and mental censorship. In all lines of human activity a mighty upheaval, uplift and upgrowth was in progress, and the genesis and development of various sciences was proceeding with great vigor. Lord Bacon (1561-1626) had pointed out the inductive method a method repugnant to the ancient and medieval mind. -by which alone knowledge could be placed on a sound basis. Sydenham's century saw Galileo (1564-1642) and Kepler (15711630) in astronomy, Newton (1642-1727) in physics, Harvey (1578-1637) in physiology. It saw the early advances in microscopy, histology, zoölogy and botany. The Royal Society, a powerful influence in the promotion of scientific research, was founded in 1660, and the brilliant thinkers who formed its early membership were contemporaries and neighbors of Sydenham.

Medicine had made very little advance since the time of Hippocrates, two thousand years before the Renaissance. The awakening in medical science first showed itself in the 16th century in the development of anatomical knowledge, under Jacobus Sylvius (1478-1555), Eustachius (1500-1574), Vesalius (1514-1564),

* Read before the Medical Society, May 5, 1909.