TABLE SHOWING THE AVERAGE TYPHOID DEATH RATE PER 100,000 FOR A PERIOD PRIOR TO THE IMPROVEMENT IN THE WATER SUPPLY, THE AVERAGE TYPHOID DEATH RATE PER 100,000 SINCE THE CHANGE IN THE WATER SUPPLY, AND THE PERCENTAGE OF REDUCTION CAUSED BY THE IMPROVEMENT;

THE TYPHOID EPIDEMIC AT LAUSEN, SWITZERLAND.-The epidemic of typhoid fever which occurred in Lausen, Switzerland, in 1872, was the first to attract general attention, "and, because of certain peculiar conditions connected with it, and especially because of its influence upon the theory and practice of the purification of water by filtration, it deserves the most careful consideration by all students of sanitation." It is also interesting because of the remoteness and unusual method by which the infection reached the water supply. The following account of this epidemic is from the description by Sedgwick, quoting Dr. Hagler's report:

The epidemic occurred in the little village of Lausen in the canton of Basel in Switzerland in August, 1872. Lausen was a well-kept village of 90 houses and 780 inhabitants, and had never, so far as known, suffered from a typhoid epidemic. For many years it had not had even a single case of typhoid fever, and it had escaped cholera even when the surrounding country suffered from it. Suddenly, in August, 1872, an outbreak of typhoid fever occurred, affecting a large part of the entire population.

A short distance south of Lausen is a little valley, the Fürlerthal, separated from Lausen by a hill, the Stockhalden, and in this valley, on June 19, upon an isolated farm, a peasant, who had recently been away from home, fell ill with a very severe case of typhoid fever, which he had apparently contracted during his absence. In the next two months there occurred three other cases in the neighborhood-a girl, and the wife and son of the peasant.

No one in Lausen knew anything of these cases in the remote and lonely valley, when suddenly, on August 7, ten cases of typhoid fever appeared in Lausen, and by the end of 9 days 57 cases. The number rose in the first four weeks to more than one hundred, and by the end

(From "Conservation of Life and Health by Improved Water Supply " by George M. Kober.) 1. From unfiltered river supply to filtered river supply. 2.-From unfiltered river supply to wells. 3.-From polluted river supply to conserved river supply.

FIG. 113.-MEAN DEATH RATES FROM TYPHOID FEVER, 1902 TO 1906, IN 66 AMERICAN

CITIES AND 7 FOREIGN CITIES. GROUPED ACCORDING TO THEIR DRINKING WATER. The rates for foreign cities are taken from James H. Fuertes.

(From "Conservation of Life and Health by Improved Water Supply " by George M. Kober)

of the epidemic in October to about 130, or seventeen per cent. of the population. Besides these, fourteen children who had spent their summer vacation in Lausen fell ill with the same disease in Basel. The fever was distributed quite evenly throughout the town, with the exception of certain houses which derived their water from their own wells and not from the public water supply. Attention was thus fixed upon the latter, which was obtained from a well at the foot of the Stockhalden hill on the Lausen side. The well was walled up, covered, and apparently protected, and from it the water was conducted to the village, where it was distributed by several public fountains. Only six houses used their own wells, and in these six there was not a single case of typhoid fever, while in almost all the other houses of the village, which depended upon the public water supply, cases of the disease existed. Suspicion was thus directed to the water supply as the source of the typhoid, very largely because no other source could well be imagined.

There had long been a belief that the Lausen well or spring was fed by and had a subterranean connection with a brook (the Fürler brook) in the neighboring Fürler valley; and since this brook ran near the peasant's house and was known to have been freely polluted by the excreta of the typhoid fever patients, absolute proofs of the connection between the well of Lausen and the Fürler brook could not fail to be highly suggestive and important. Fortunately, such proofs were not far to seek. Some ten years before observations had been made which had shown an intimate connection between the brook and the well. At that time, without any known reason, there had suddenly appeared near the brook in the Fürler valley below the hamlet a hole about eight feet deep and three feet in diameter, at the bottom of which a considerable quantity of clear water was flowing. As an experiment the water of the little Fürler brook was at that time turned into this hole, with the result that it had all flowed away underground and disappeared, and an hour or two later the public fountains of Lausen, which, on account of the dry weather prevailing at the time, were not running, had begun flowing abundantly. The water from them, which was at first turbid, later became clear; and they had continued to flow freely until the Fürler brook was returned to its original bed and the hole had been filled up. But every year afterward, whenever the meadows below the site of the hole were irrigated or overflowed by the waters of the brook, the Lausen fountains soon began to flow more freely. In the epidemic year (1872) the meadows had been overflowed as usual from the middle. to the end of July, which was the very time when the brook had been infected by the excrements of the typhoid patients. The water supply of Lausen had increased as usual, had been turbid at the beginning, and had had a disagreeable taste. And about three weeks before the begin

ning of the irrigation of the Fürler meadows typhoid fever had broken out, suddenly and violently, in Lausen.

In order to make matters, if possible, more certain the following experiments were made, but unfortunately not until the end of August when the water of the Lausen supply had again become clear. The hole which had appeared ten years earlier, and had afterward been filled up, was reopened, and the little brook was once more led into it; three hours later the Lausen fountains were yielding double their usual volume. A quantity of brine containing about eighteen hundred pounds of common salt was now poured into the brook as it entered the hole, whereupon there appeared very soon in the Lausen water first a small, later a considerable, and finally a very strong reaction for chlorin, while the total solids increased to an amount three times as great as before the brine was added. In another experiment five thousand pounds of flour (Mehl), finely ground, were likewise added to the brook as it disappeared in the hole; but this time there was no increase of the total solids, nor were any starch grains detected in the Lausen water.

It was naturally concluded from these experiments that while the water of the brook undoubtedly passed through to Lausen and carried with it salts in solution, it nevertheless underwent a filtration which forbade the passage of suspended matters as large as starch grains. Dr. Hägler, from whose report the foregoing facts are taken, was careful, however, to state that "it is not denied that small organized particles, such as typhoid fever germs, may nevertheless have been able to find a passage." As a matter of fact Dr. Hägler's minute account does to-day give us some indication that such germs might easily have passed from the brook to Lausen, for the turbidity of which he repeatedly speaks is evidence of the passage of particles as small as, and possibly smaller than, the germs of typhoid fever.1

Unfortunately this was before pure cultures of bacteria were known, and no experiments were made with suspended matters as small as bacteria. The conclusion was inevitable that although filtration had in this case sufficed to remove starch grains, it had been powerless to remove the germs of typhoid fever; and, accordingly, filtration as a safeguard against disease in drinking water fell for a time into disrepute.2

THE TYPHOID EPIDEMIC IN PLYMOUTH, PENN.-In 1885 the mining town of Plymouth, Penn., with a population of about 8,000, suffered with a severe outbreak of typhoid fever which involved one in every eight of the inhabitants. Plymouth received its water from a mountain

"Typhus und Trinkwasser," Vierteljahresschrift für öffentliche Gesundheitspflege, VI, 154; also Sixth Report, Rivers Pollution Commission of 1868, London, 1874.

2 See paper by Sedgwick on "The Rise and Progress of Water Supply Sanitation in the Nineteenth Century," Journal New England Water Works Association, XV, 1901, p. 330, No. 4.