taught, but they should be examined regularly in schools, in order that their health and vision may be safeguarded. The care of the individual case is largely a surgical matter. These points are brought out in a short paper printed in the Public Health Reports and issued as Reprint No. 296.

TRICHINOSIS.

The recent occurrence of several outbreaks of trichinosis in the United States serves to direct attention again to this disease. In 1901 Prof. Stiles, of this service, compiled about 900 cases of the disease for this country from 1841 to 1900, inclusive, and Dr. B. H. Ransom, of the United States Bureau of Animal Industry, has brought the compilation down to 1915 by adding about 650 cases, making a total of about 1,550 cases, with 240 deaths. The States which have had the highest number of recorded cases are: New York, 355 cases, 62 deaths; Pennsylvania, 261 cases, 16 deaths; Massachusetts, 145 cases, 13 deaths; Minnesota, 101 cases, 12 deaths; California, 91 cases, 9 deaths; Illinois, 90 cases, 24 deaths.

According to results of microscopic examination by the United States Department of Agriculture more than 14 out of every 1,000 hogs slaughtered in this country contain a small parasite, known as Trichinella spiralis, and more than 25 out of every 1,000 of these hogs contain either this worm or bodies resembling the cysts of this

worm.

If taken alive into the human body this parasite, known ordinarily as trichina, is capable of producing trichinosis, and statistics of 14,820 cases in man collected by Prof. Stiles, of this service, show that 5.6 per cent were fatal. But if the worms are killed by thoroughly cooking the pork, they will not produce this disease.

Uncertainty of microscopic inspection. The meat inspection conducted under the Federal laws and under the regulations promulgated by the Department of Agriculture does not include an inspection for the presence of trichina in hogs. Experience shows that the microscopic inspection for trichina conducted in some countries is weakened by such an incidence of error and uncertainty that it is untrustworthy and eliminates from the trade only part of the trichinous meat. Neither meat-inspection systems nor meat dealers are in a position to give scientific assurance that pork, even if inspected microscopically, does not contain this infection. The service has therefore issued the warning that in spite of any assurance to the contrary it is not safe to eat even microscopically inspected pork unless this has been thoroughly cooked or treated by some other safeguarding process that kills the trichinæ.

TYPHOID FEVER.

EPIDEMIC AT GALLUP, N. MEX.

Study of an epidemic of typhoid fever at Gallup, N. Mex., during September and October, 1915, was made by Surg. F. C. Smith, on directions from the bureau. It was determined that the epidemic, which was mild in character, was almost certainly caused by milk infection. A flood occurred early in September, washing out of the

river bed the accumulated sewage of several weeks, which was carried to a farm below furnishing milk to the city. Of 65 cases in which the epidemiological data were fairly clear, 61 gave a history of having taken milk from this farm, either as a beverage, on cereal, or in milk or malted milk shakes at a soda fountain. The large number of children in this series of cases-41 under the age of 18would at once suggest the probability of milk infection, were other facts concerning the milk supply unknown.

It was not determined where the preepidemic cases received infection, but it is thought probable that typhoid fever was constantly present in the city from midwinter to September 5, the date of the flood, and that the sewage delivered into the river was contaminated with typhoid bacilli. The explosive outbreak which occurred September 18 fulfilled the conditions imposed by the incubation period of the disease, which is from 8 to 21 days.

During the investigation, studies of the water supply and other conditions possibly affecting the epidemic were made. A report recommending a course to be pursued to prevent a recurrence of the epidemic was made to the mayor of Gallup and published in the Public Health Reports of January 14, 1916.

SURVEY OF ORIGIN OF TYPHOID-FEVER CASES.

In connection with the study of the pollution of coastal waters, Surg. H. S. Cumming made inquiries into the origin of a series of outbreaks of typhoid fever in Illinois, Indiana, Pennsylvania, and New York, as a result of which insanitary conditions were found in various shellfish shucking houses. (See p. 77.)

TYPHUS FEVER.

INVESTIGATION OF CASE IN BALTIMORE, MD.

On September 3, 1915, Asst. Surg. M. H. Neill was directed to proceed to Baltimore for conference in relation to a suspected case of typhus fever. In view of a characteristic clinical picture, especially the exanthem, and the fact that other affections of a similar appearance could be ruled out, it was concluded that the case was one of typhus fever, in spite of the lack of any history of near or remote contact with preceding cases of typhus fever which have occurred in Baltimore.

The above case emphasizes the liklihood of the undue prevalence of typhus fever in our large centers of population. Investigations had previously shown that the disease had prevailed for many years in one such center, the disease being recognized under another name. While no great spread of the infection is to be expected, it is evident that physicians and sanitarians should be on the lookout for such cases.

OCCUPATIONAL DISEASES AND INDUSTRIAL HYGIENE.

Investigations of occupational diseases and the hygiene of workers during the past fiscal year, under the general direction of Surg. J. W. Schereschewsky, have been somewhat extended. In con

formity with the policy of establishing public-health stations in various sections of the United States, the field headquarters were transferred to Pittsburgh, Pa., during July, 1915. It seemed fitting that field headquarters devoted to this purpose should be established in a large industrial center.

In order to provide facilities for research work suitable laboratories have been established in the Pittsburgh Marine Hospital. The clinical laboratory, consisting of a room 16 by 25 with two adjoining rooms each 12 by 12, was converted into a physical laboratory for the purpose of making studies of the hygiene of illumination. The laboratory has been provided with apparatus for this purpose.

On the second floor of the hospital one room, 65 by 28 feet, was converted into a series of laboratories-bacteriological, physiological, and chemical, respectively-for the purpose of studying problems relating to occupational diseases and industrial hygiene involving these lines of research.

EFFECT OF GAS-HEATED APPLIANCES UPON AIR OF WORKSHOPS.

During the past fiscal year the work of investigating the effects of certain gas-heated appliances upon the air of workshops was completed. This work was incidental to a study of the health of garment workers, undertaken at the solicitation of and in cooperation_with the joint board of sanitary control of the Cloak and Suit and Dress and Waist Trades of New York City. The results of this study were published in Public Health Bulletin No. 71. As the use of gasheated pressing irons is general in the women's garment industry it became desirable, during the course of the general investigation just mentioned, to study the extent to which garment workers as a class, and pressers in particular, are exposed to the health hazards incident to the use of gas-heated pressing appliances.

This study was made by Sanitary Chemist Charles Weisman, under the general direction of Surg. J. W. Schereschewsky. The laboratory work was done in the chemical laboratories of Cornell Medical School, through the courtesy of the faculty of the medical school.

The general scope of this investigation was as follows:

1. Analyses of air samples taken in shops of the garment industry with reference to the amount of carbon monoxid gas present and studies of the condition of gas-heated appliances.

2. Laboratory examinations of the gaseous combustion products of various kinds of gas-heated pressing irons.

3. Tests of the permeability to gas of the walls of various kinds of flexible gas tubing and of the security against leakage of gas con

nections.

4. The hygienic significance of the presence of small amounts of carbon monoxid in the air of confined inhabited places.

Analyses of air in workshops.-During the course of the study air samples were obtained from 244 shops of the women's garment trades. Two samples were taken on each occasion, one from the vicinity of pressing irons, the other from a situation near a window as far removed as possible from sources of air contamination.

In 29 shops, or 11.8 per cent of the total number, the amount of carbon monoxid present in the vicinity of pressing irons was over

100 parts to the million of air. The average amount of carbon monoxid present in these shops was 325 parts to the million of air, the maximum being 1,431 parts, while the minimum was 105 parts. Of the samples taken in these shops near windows, at points as far away as possible from sources of contamination, the amounts of carbon monoxid present ranged from 2 to 39.6 parts per million of air, or an average carbon-monoxid content of 11.8 parts per million.

It is evident from the figures just given that the contamination of the air of the shops examined was significant only in the vicinity of pressing irons. Pressers, therefore, are the group of garment workers particularly exposed to the hazard of chronic poisoning by carbon monoxid. In considering the results of the air analyses, however, it should be considered that this study was made during the openwindow season, when nearly all the shop windows were open. In the shops studied there was very little attempt to provide any aids to natural ventilation. No mechanical exhaust system was used in any of the shops visited. Electric fans were provided in only 6 per cent of the shops inspected. Less than one-half of such places used the fans. An odor of gas was perceptible in 93 establishments, or in 38 per cent of the total number. Of 29 shops in which the amount of carbon monoxid present exceeded 100 parts per million, an odor of gas was present in 27.

In many instances defective tubing was found conveying gas to pressing irons. Such defective tubing was found in 66 shops, or in about 27 per cent of the total number. Of the 244 shops studied, 122, or 50 per cent, used ordinary gas irons only; 102 shops, or 41.8 per cent used "blower" irons exclusively, while the rest used miscellaneous irons.

In

That the amounts of carbon monoxid found in the air of workshops were not fortuitous was shown by the results of reinspections. În some instances the amounts of this gas found at a second visit exceeded that present at the first examination.

The sources of carbon monoxid in the air of workshops of the women's garment industry were found to be:

(a) Defective combustion of gas in pressing irons.

(b) Diffusion of illuminating gas through the walls of gas hose not visibly defective.

(c) Leakage from defective gas connections and defective gas hose. These three sources of the contamination of air with carbon monoxid were therefore investigated.

Combustion products of pressing irons.-Two general types of gas pressing irons are in general use in the women's garment trades, (1) pressing irons burning a mixture of gas and air at atmospheric pressure and (2) pressing irons in which the gas and air mixture is supplied under pressure by means of blowing apparatus. Consideration of the construction and analyses of the combustion products of the atmospheric iron in many instances showed that the combustion of the gas-and-air mixture is defective. In one instance per cent of carbon monoxid was found in the combustion products of one type of atmospheric iron, while the average for eight different makes was 0.57 per cent. The combustion products from an improved type of atmospheric iron and those from properly adjusted "blower" irons failed to show the presence of carbon monoxid in significant amounts, although small quantities were present.

2

Permeability of walls of gas tubing and gas connections to illuminating gas. Some 68 tests were made of the permeability to illuminating gas of the walls of gas hose.

The results of these tests show, (1) that none of the tubing tested was found to be perfectly gas tight, (2) that the permeability of new tubing is increased if gas be passed through it for a certain period (30 to 60 hours) before making the test, (3) that rubber tubing is the least permeable to gas, and, finally, (4) that the walls of flexible metal tubing and "composition" tubing give considerable leakage of illuminating gas.

The rubber ends used to connect gas hose with gas irons and with sources of gas supply were found to be prolific sources of gas leakage. Laboratory tests made upon new connections showed that these were by no means gas tight. In practice, the heat generated by gas irons, as well as the constant to-and-fro motion to which they are subjected causes these connections, too frequently made of scrap rubber and possessing but little inherent elasticity, to expand and to lose the little elasticity originally present so that considerable quantities of illuminating gas escape into the air. The ends also frequently become loosened or entirely detached from the gas tubing, thus leading to crude and ineffectual attempts on the part of the user to make them gas tight by bandaging with tape, rags, and the like.

Hygienic significance of small amounts of carbon monoxid.-It was evident from the foregoing studies that the opportunities are numerous for the contamination of the air of workshops of the women's garment trades with carbon-monoxid gas, and that pressers must frequently be exposed to the risks of chronic poisoning. This gas possesses such affinity for the hemoglobin of the blood that even small quantities in the air of interiors may be detrimental to Health. While we are, as yet, without exact standards as to the minimum amount of carbon monoxid which may be present, without causing harmful effects, in the air of interiors, it is probable that quantities of this gas in excess of 200 parts per million of air exert à deleterious influence upon those continuously exposed to such atmosphere. Carbon monoxid in excess of the proportions just given was found present in a number of instances in the air of the workshops studied.

Freedom from the hazard of carbon-monoxid poisoning due to the use of gas-heated pressing irons can be secured only by the use of approved types of gas irons, carefully selected rubber tubing, gastight connections, and a well-devised system of frequent inspection and constant maintenance. The hazard of chronic carbon-monoxid poisoning may be eliminated by the use of electrically heated pressing irons.

The results of this investigation are being published as Public Health Bulletin 81.

RELATION OF HEALTH OF GARMENT WORKERS TO ECONOMIC STATUS.

Data obtained in the investigation of garment workers in New York City were analyzed by Surg. B. S. Warren and Public Health Statistician Edgar Sydenstricker in a paper printed in the Public Health