boys and girls, workers in stores, factories, shops, etc., living in New Jersey or Connecticut and having employment in the city. This was cared for by the issuance of commuters identification cards, based on information similar to that required for interstate travel as to the freedom of their premises from this disease, but with the provisions that these cards should be renewed every week under like conditions of immunity.

It will thus be apparent that the measure adopted by the United States Public Health Service was a frank inspection and notification system, and nothing else. A quarantine of New York City was not only impracticable, but undesirable and unadvisable under the circumstances. That the system had the effect of restricting travel from uncertified premises, and children in a doubtful state of health is established by the experience of the medical inspectors, and records of the work.

Indirectly, the travel and congregation of children for the customary week-end excursions at the beaches, was discouraged. As this was mostly interstate travel, mixed with interstate traffic, it could be done only through the co-operation of the boards of health of the adjoining states, and the transportation companies. Certification of such travel was absolutely refused by me on the ground that it tended to spread the disease by contact of persons from infected localities with persons from uninfected localities. Baby parades at Asbury Park, Atlantic City and other shore resorts, and similar congregations of children for like purposes at fairs and yearly celebrations of various sorts were effectively stopped through notification to the respective managers of such affairs, and the great annual volksfest of the United German Societies of New York, held annually in Bergen, New Jersey, was also stopped as far as the participation of children was concerned, by the application of the same restrictive methods. It is estimated that 10,000 children annually attend this latter national gathering.

Arriving on the scene after the epidemic had reached a total of 2,000 cases of infantile paralysis, and with summer travel already begun and in operation for several weeks, it will be understood that thousands of children had already left the infected area and had been distributed in hundreds of places in New York, New England, New Jersey and Pennsylvania. As a consequence of this early and unrestricted movement of children, various portions of Connecticut insti

tuted quarantines of varying rigidity, and this was followed by similar action on the part of towns in New York State and New Jersey. The State of Pennsylvania adopted stringent quarantine measures effective August 4, and on August 15 New Jersey required the restriction of all travel of children 16 years of age or under, between towns in the state. The State of Virginia adopted the most repressive quarantine measure, denying admission to any child into the state, but illogically excepting residents of that state from its operation; and some communities in the middle and far west maintained a system of travel inspection.

The objects achieved, from the standpoint of those engaged in this work in New York City, may be stated as warranting the following conclusions:

First. The stabilization of public opinion through the presence of regular officers of the United States Public Health Service, trained in the management of epidemics, who were assigned to duty in New York City. This was crystalized through the uniform approval of the metropolitan press, with its continuous favorable references to the work accomplished.

Second. The standardization of methods adopted by local quarantine officers of other states through co-operation with the plan of certification above described. Harsh restrictive measures had been adopted in many localities because of the absence of knowledge of the extent of the epidemic, and lack of information of the origin of travel into their communities.

Third. The certification of such travel, as being reasonably safe, after medical examination, which outside communities were willing to honor because issued by trained federal officers not subject to local interests. It afforded the local health authorities a certain security in locating arrivals in their jurisdiction immediately, and instituting such measures of isolation, or limitation of movements for a given period as they deemed wise.

Finally. A demonstration of the need of a centralized authority, with power to deal with interstate problems relating to the transmission of disease by common carriers, backed by Congressional statute. The Quarantine Law of February 15, 1893, was the keynote to the administration of the work of the officers of the United States Public Health Service in the measure employed by it of certification, and notification to health officers of travel to their localities.

From the standpoint of the states outside of the zone of immediate contact, the proof of the efficiency of the work should be found in the record of any cases in distant communities which could be traced to travel certified by our officers as origination in New York City.

As this meeting is held in Wisconsin, it is perhaps typical to take this state as an example with its cities and towns to which travel. was certified from July 18 to September 30, inclusive.

Of the 85,000 children certified to every state in the Union, covering nearly four thousand separate localities, our records show 105 children certified to Wisconsin, destined to 19 different localities. Inquiry was made of the health officers of all these localities, which included the city of Milwaukee, and the uniform reply was that there had either been no case of poliomyelitis, or if such had occurred, that it in no way could be connected with travel from New York City.

As an example from a distant section of the country, the State Health Officer of Florida informed me that none of the cases which appeared in his state could in any way be traced to travel certified by us from New York City. I also addressed health officers of two localities in each of twenty different states, picked at random, including localities ranging from the smallest towns to cities the size of New Orleans, and in over fifty (50) replies which I have received I was informed that wherever cases had occurred they were in no way traceable to New York travel.

The city of Holyoke, Massachusetts, is perhaps a typical example of the conditions incident to the spread of the disease this summer through certified and uncertified travel. This city became badly infected, relatively speaking, and a house to house inspection was undertaken to locate the families arriving there from New York prior to the institution of our inspection and a considerable number of the cases which appeared in Holyoke could be traced to that source. After July 18 twenty-six families were certified by us to that city and were placed under quarantine observation. No case occurring in the city could be traced directly to these twenty-six units, or for that matter, no case that developed in close proximity to their residences. These facts are based on a sanitary survey of Holyoke in relation to epidemic poliomyelitis, made by a responsible official.

I give these facts for what they are worth. With our lack of knowledge as to the method of transmission of the disease, whether by

adult or child carriers, or by other means, the claim can be as readily made that the measures instituted and carried out by the United States Public Health Service did effectually prevent the spread of the disease through interstate travel. These hundred localities selected at random from all over the United States, point to that conclusion, certainly. If poliomyelitis had been found in these localities traceable to New York travel, after July 18, it could as readily be claimed that the plan had been a failure.

The Chairman:

The quarantine game is something like a game of checkers. We make our move, the germ makes its move, and so it goes. The skill with which we humans make our moves depends on our knowledge of the probable moves of the germ, and if we are to play the game well we must study the methods habitually followed by the germ that is responsible for the outbreak. So while Dr. Banks has been busy making the moves designed to checkmate and block the virus, Dr. Frost has been studying the habits of the disease so as to assist by giving us some knowledge of the probable moves the virus is going to make.

It gives me pleasure to introduce Dr. Wade H. Frost, Passed Assistant Surgeon, U. S. Public Health Service, Washington, who will tell us something of epidemiologic studies of infantile paralysis.

THE ACTIVITIES OF THE UNITED STATES PUBLIC HEALTH SERVICE

IN EPIDEMIOLOGIC STUDIES OF INFANTILE PARALYSIS

WADE H. FROST, M. D., Passed Asst. Surg., U. S. Public Health Service, Cincinnati

A well balanced estimate of the public health importance of almost any infectious disease and effective methods of control are usually based on knowledge derived from different angles of study; primarily from clinical study showing the nature of the manifestations of the disease, often from experimental work, giving knowledge of the specific organism and pathogenesis; almost invariably in addition to these, from epidemiologic studies. The term "epidemiologic study” as used here is intended to mean not merely studies of epidemic outbreaks but also of the circumstances and conditions governing the usual occurrence of the disease in nature, such circumstances as the relation of cases to each other and to various environmental conditions.

The relative importance of these various angles of study differs in different diseases. Regarding certain common infectious diseases, such as measles, scarlet fever and smallpox, we have arrived at our present conception of their etiology without material aid from experimental studies. In certain other diseases notably yellow fever, malaria and bubonic plague, the results of experimental studies have completely revolutionized previous conceptions regarding etiology and prevention.

The field of epidemiologic study is peculiarly one for governniental agencies, federal, state and municipal, because the primary data necessary for such studies, namely, morbidity reports, can best be obtained through the agency of the constituted public health authorities. This is not so in clinical or experimental studies which consequently have been developed largely by research institutions and individuals, not connected with the organized public health authorities.

Before undertaking to give a review of the studies undertaken by the Public Health Service in connection with the poliomyelitis epidemic of this year, it may be well to review briefly what had been done in this field in previous years.

Prior to the Swedish epidemic of 1905 no co-ordinated records of poliomyelitis were available, because there had been nothing more than