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The Work of a Chronic Typhoid Germ Distributor, George A. Soper, Ph.D.



Consider These Questions


George Soper was a civil engineer hired by private citizens of New York City to investigate the outbreak of typhoid in Oyster Bay, New York. He was known for his experience in investigating typhoid fever epidemics using epidemiological analyses. This paper about his investigation of Mary Mallon was read before the biological society of Washington, D.C., on April 6, 1907.

In the winter of 1906 I was called on to investigate a household epidemic of typhoid fever which had broken out in the latter part of August at Oyster Bay, N. Y. The epidemic had been studied carefully immediately after it took place, but its cause had not been ascertained with as much certainty as seemed desirable to the owner of the property.

The essential facts concerning the investigation follow:


At Oyster Bay in the summer of 1906 six persons in a household of eleven were attacked with typhoid fever. The house was large, surrounded with ample grounds, in a desirable part of the village, and had been rented for the summer by a New York banker.

The first person was taken sick on August 27 and the last on September 3. The diagnosis of typhoid was positive. Two of the patients were sent to the Nassau hospital at Mineola. The others were attended by capable physicians at Oyster Bay. None of the subsequent cases apparently resulted from the first, although the interval from the first to the last might permit of this assumption. But whether the disease was transmitted from one person to another after the first case occurred was not a matter of great consequence. The most important question was how the first case occurred.

Typhoid fever is an unusual disease in Oyster Bay, according to the three physicians who share the medical practice there. At the time of the outbreak no other case was known. None followed.

The milk supply of this house was the same as used by most of the other persons in the village, all of whom [remained well.] The cream also was from a source which supplied several other families in the vicinity.

To the first investigators it seemed that the water must have been contaminated. They were unable to ascribe the fever to food, flies or milk, whereas if they could discover that the water had been contaminated they would be able to account for the epidemic.

The water supply for the house was from a driven well said to be 167 feet deep. The well was at a distance of 210 feet from the house, within 60 feet of a stable drain, 115 feet from a privy behind the stable, and 224 feet from two cesspools which received the drainage of the house. The cesspools and privy had been cleaned out in April. The house was provided with one water closet, situated on the second floor. This was used by the family. The sic servants used the privy. The sewage from the house was carried by a tile pipe to the two cesspools just referred to. The soil is sandy and gravelly throughout this region.

The water was pumped from the well by a gas engine to a covered wooden tank situated 186 feet from the stable and 320 feet from the house. Water ran from this outside tank to an open tank in the attic of the house, removed from the nearest living rooms by a steep and narrow ladder.

Samples of the water were taken and subjected to careful chemical and bacteriologic analysis. They were collected direct from the pump, from the outside tank and from a faucet in the house. There were five samples taken in all. Four were examined by E. E. Smith, M.D., Ph.D., the well-known analytic expert, and the other by D. D. Jackson, Ph.D., director of the laboratories of the New York City Department of Water Supply, Gas and Electricity.

The essential facts concerning these analyses, including the condensed statements of the resulting opinions, follow:


1906      Source of Sample      Opinion of Analyst

Sept. 12.–Faucet in house……. "Sanitarily pure."–Dr. Smith.

Sept. 12.–Outside tank……….. "Probably safe."–Dr. Smith

Sept. 13.–Pump over well……. "No evidence of pollution."–Dr. Smith

Sept. 27.–Outside tank……….. "Typhoid from this source impossible."–Dr. Jackson

Sept. 29.–Outside tank……….."Evidence does not show pollution."–Dr. Smith

In addition to these examinations, an experimental study was made of the possibility that the typhoid germs might have percolated through the ground to the well from some receptacle of excrement. On September 29 Dr. Smith put fluoresein in the bowl of the water closet in the house, in the cesspools, in the stable manure vault, in the privy vault on this property and in another on adjacent property and in the bowl of the water closet in a neighboring house. He looked for traces of this fluoresein in water from the well, obtained after much pumping, two days and five days later. Six samples of water were collected during this test. They entirely failed to reveal pollution.

Even this thorough work on the water supply did not entirely destroy local confidence in the theory that the water had been the cause of the outbreak. A contamination of the outside covered tank of such nature as to escape detection by analysis was suspected as offering a possible explanation of the trouble. According to this idea the tank, which had been cleaned early in the spring, might have received typhoid bacilli from the cleaners who, perhaps, carried typhoid excreta on their boots. It was supposed that a gradual accumulation of organic matter from the water and dust from the air, aided by the continued warmth of the summer sun, might have led these germs to multiply until at last they escaped to the water and infected the household.

It did not seem to me that the water theory was tenable. The analyses proved that the well was not continuously polluted. The fluoresein tests showed that occasional contamination was not likely. An inspection of the premises and inquires concerning they way the outside tank was cleaned made it seem unlikely that this tank became infested in the way supposed.

It would have been more probable to suppose that the tank in the house, which was without a cover and accessible to occupants of the house, had become polluted. Such contamination was not without precedent. Had typhoid existed in the house at the time, it was possible that the tank could have become contaminated in this way. But there had been no case. Moreover, inquiry made it seem unlikely that the tank had been visited all summer. It was much more convenient for persons to get water otherwise than by climbing the narrow ladder to the attic. It seemed more probable that they infectious material had been carried to the house by some person or some article of food.

I was led from the proper track for a time by being assured that no person who had had typhoid, at least within many months, had lived in the house or visited it during the whole summer, and by discovering that the family was extremely fond of soft clams. My suspicion for a time attached to clams. It was found that soft clams had frequently been obtained in the summer from an old Indian woman who lived in a tent on the beach not far from the house. It was impossible to find this woman, but I made inspections of the sources of soft clams at Oyster Bay, which showed that they were sometimes taken from places where they were polluted with sewage.

But if clams had been responsible for the outbreak it did not seem clear why the fever should have been confined to this house. Soft clams form a very common article of diet among the native inhabitants of Oyster Bay. On inquiring closely into the question of the food eaten before the outbreak it was eventually found that no clams had been eaten subsequent to July 15. This removed the possibility that they epidemic had been caused by clams. From July 15 to August 27, six weeks, was too long a period for an outbreak of this character to remain undeveloped. The infectious matter which produced the epidemic had been taken with food or drink, in my opinion, on or before August 20.

The supplies of vegetables and fruit were next considered. It was found that they persons attacked had not eaten any raw fruit or vegetables which had not also been eatene by menay persons who escaped the fever.

The history of the house with regard to typhoid was inquired into. It was found that but one case of typhoid had occurred on the premises or been nursed there in thirteen years. This case occurred in 1901. Care seemed to have been taken to destroy the infectious nature of the discharges. The case produced no secondary cases at the time. The house had been occupied every summer since without typhoid.

Attention was now concentrated for a time on the first cases to determine whether the infection could have occurred during a temporary absence from Oyster Bay. It was found that those persons who were taken sick at the outset had not been on a visit, or picnic, or, in fact, away from Oyster Bay on any account for several weeks prior to the onset of the illness.

The social position of the persons attacked differed decidedly. Among the first to be taken sick were a daughter of the head of the family and two maid servants, one of which was colored. Following in a quick succession were the wife and then another daughter of the tenant and, finally, the gardener who lived permanently at Oyster Bay and had worked on the place for years.

Believing that some peculiar event might have occurred in the family on or shortly before August 20, which, if studied, might give the necessary clue to the cause of the epidemic, careful inquiry was made into the immediate history of the household at this time. The key of the situation was thus discovered.

It was found that the family had changed cooks on August 4. This was about three weeks before the typhoid epidemic broke out. A cook who had been with the family several years had been discharged and a new one employed. Little was known about the new cook’s history. She had been engaged at an employment bureau which gave her an excellent recommendation. She remained in the family only a short time, leaving about three weeks after the outbreak of typhoid occurred. Her present whereabouts were unknown. The cook was described as an Irish woman about 40 years of age, tall, heavy, single. She seemed to be in perfect health.

Here was by all means the most important possibility in the way of a clue which had come to my notice. If this woman could be found and questioned, it seemed likely that she could give facts from which the cause of the epidemic could be ascertained.

When, after much difficulty, she was found, this hope was destroyed. No information of value was obtainable from her. She refused to speak to me or any one about herself or her history except on matters which she knew were already well known.

It became necessary to work out the cook’s history without her help. This effort has been only partially satisfactory. Her whereabouts for only a part of the time in the last ten years have been ascertained. About two years of time among the last five years remain unaccounted for. In the last ten years she has worked for eight families to my positive knowledge; in seven of thse typhoid has followed her. She has always escaped in the epidemics with which she had been connected.

The most interesting features of the other outbreaks of typhoid with which this cook has been connected follow:

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