Senior Surgeon C. C. Pierce, in charge of the general supervision of service quarantine stations along the Mexican border, reports in detail as follows:

The service work along the border to prevent the introduction of typhus from those districts where it is prevalent in Mexico has been vigorously carried on during the fiscal year with increased personnel and equipment at various points along the border. The measures effected on the border were as satisfactory as could be expected, in view of the difficulty of maintaining quarantine restrictions on a boundary line 1,300 miles in length from El Paso to the Gulf, presenting no material natural obstacles to travel. From El Paso to the Pacific Ocean the boundary between Mexico and the United States is 719 miles in length, but the western Mexican States of Sonora and Lower California have fortunately been comparatively free from typhus fever. This presumably is due to the difficulty of travel between this section of Mexico and the typhus-infected plateau region of that country. Cases of typhus have not been reported as entering the United States at any border point west of El Paso, Tex.

During the latter part of the last fiscal year it was found from experience that the utilization of disinfecting plants located on Mexican territory and operated by Mexican officials was not satisfactory, although an employee of the service was stationed at each plant in a supervisory capacity. No standard could be enforced in regard to the hours of operation nor the control of persons and their effects after disinfection. The operation of these rehabilitated Mexican plants was commenced during the winter of 1915-16 to meet an urgent necessity at a minimum expenditure, and was only intended as an expedient.

The

The bureau, therefore, in the summer of 1916 began to devise plans for the erection of fully equipped disinfecting plants on American territory, at the various border points where they were required and to arrange for their construction before the onset of cold weather, at which time it was anticipated that there would be a considerable increase in the number of cases of typhus. officer in charge of the work along the Mexican border in September, 1916, was directed to arrange as rapidly as possible for the location and construction of plants at the various border ports. The plans of the plants required were drafted and approved, and orders were placed for the necessary equipment, including steam sterilizing chambers.

In establishing these plants many unforeseen contingencies were encountered, thus delaying the operation of the disinfecting stations. One source of delay was the impracticability at some of the border towns of securing title to suitably located sites upon which the plants could be erected. This made it necessary at some of the border ports of entry to make arrangements with local property owners for the erection of special buildings to be rented for quarantine purposes to the Government. This procedure was followed at El Paso, Brownsville, and Hidalgo, Tex. At Eagle Pass and Rio Grande City, Tex., sites were secured from the War Department on military reservations and the plants were constructed by the service. At the port of Laredo a suitable site was finally leased from the railroad company at a nominal sum and the erection of a quarantine plant upon this location was started, the construction to be completed and in operation by the latter part of July, 1917.

At El Paso the quarantine plant is located at the American end of the international foot bridge, adjacent to the United States immigration station. The street cars run between El Paso, Tex., and Juarez, Mexico, across this bridge, and the international railroad bridge is only a short distance away, so that the plant is easily available for the treatment of all traffic, even when the railroad service is resumed. The El Paso plant was completed during the last days of December, and was opened for service on January 2, 1917. Prior to that time the vermin-infested travelers desiring to enter the United States at that place were treated at the Mexican plant in Juarez under the supervision of an inspector of the service.

David M. White, while on this duty, contracted typhus fever and died October 19, 1916.

Since the El Paso plant has been in operation all persons crossing from Juarez, local travelers as well as immigrants, are deloused as required. From January 2 to January 27 night traffic from Juarez was permitted, but on the latter date quarantine inspection and treatment of travelers was restricted to Juarez from

7 a. m. to 7 p. m., in accordance with the general requirements of the United States quarantine regulations. Some exceptions were made by giving passes to certain officials, physicians, and other well-known persons, whose duties might require them to return from Mexico after 7 p. m. This was necessary to control the travel of vermin-infested persons after night closure of the disinfecting plant. Enforcement of the night closing order caused considerable opposition at first, and resulted in some rioting by the peon class on the international bridge, and the suspension of street car service for a few days. The opposition soon subsided, however, as closing the port at night had the indorsement of all Federal, State, and municipal officials, as well as the approval of the El Paso Chamber of Commerce, and the support of all legitimate business interests of the city.

All persons, including local residents of Juarez and El Paso now entering the United States at El Paso are required to undergo disinfection of personal effects at the quarantine plant, as occasion may arise. The "locals" are required to take the bath and have their clothing disinfected at least once each week. This measure resulted in a very marked improvement of the peon class living in Juarez and in El Paso, since they have readily grasped the fact that louse infestation seriously interfered with their movements and to a certain extent caused restriction of their travel. They are now making an effort to keep themselves clean and vermin free.

As an additional precautionary measure to prevent the spread of typhus fever from border ports of entry to other places within the States, and to prevent in a large measure the travel of those Mexicans who might enter the country clandestinely, an order was issued to all transportation companies operating trains from border towns, directing that no Mexicans of the laboring class or their families be furnished transportation unless they presented a service certificate of disinfection. (Details of these operations are recorded under the transactions of the Domestic Quarantine Division.)

It may be stated that the Mexican colonies in American cities on the border differ in no respect as to their sanitation nor as to habits and living conditions of the inmates from the habitations of the lower class Mexicans on Mexican territory.

Typhus infection having gained access to El Paso in the summer of 1916, the infection appeared to take firm hold with the establishment of several foci of infection in the city of El Paso, the cases, however, being almost entirely confined to the Mexican colony. Acting upon the request of the mayor and city council of El Paso, Asst. Surg. J. W. Tappan was given leave by the service and permitted to accept the position of health officer of the city of El Paso, for the purpose of effecting sanitary reforms in El Paso by the elimination of foci of typhus infection. Later on Asst. Surg. T. C. Galloway was also detailed by the service to assist in the sanitation of El Paso. (Details concerning this work will be found under the heading of domestic quarantine.)

Sixty-seven cases of typhus occurred in El Paso during the fiscal year and are included in tabular form in another part of this report.

At Eagle Pass, Tex., the service disinfection plant was built on the military reservation upon a site adjacent to the international footbridge and the immigration station. A small house for the inspectors was constructed at the end of the footbridge, and from this a fenced-in walk extends to the entrance of the plant. The plant was placed in operation late in January, 1917, and travel regulations were imposed similar to those in force at El Paso. At this port, where only two inbound trains leave daily, the disinfection certificates which Mexicans are required to have before boarding trains, are checked up through the cooperation of the immigration service.

When railroad passenger traffic with Mexico is resumed, those persons requiring disinfection may be removed from the Mexican train before it arrives at the Eagle Pass depot and conveyed through the military reservation to the disinfecting plant for treatment and then released.

Only two cases of typhus fever occurred at Eagle Pass during the fiscal year. The data is given with other typhus cases later in this report.

At Laredo the question of location of the service plant was carefully considered. It was at first contemplated locating the plant at the footbridge, for the reason that until recently all travel from Mexico crossed this bridge, railroad traffic having been suspended for the past two years. A suitable site near the footbridge was selected, but after prolonged negotiation it was found that no

arrangement could be made for the construction of the building required. The local representatives of the railroad company arranged to set aside a suitable site for the disinfecting plant, which is now under construction at the American end of the railroad bridge.

The quarantine building at Laredo will be two stories high, with the disinfecting machinery and bath compartments on the ground floor. The second story is arranged to provide for office and inspection space and facilities for handling first-class passengers, who may not require disinfection.

Partial travel has already been resumed over the railroad bridge at this port and upon the completion of the plant it is contemplated to require all persons entering from Mexico, except the local residents of either border town, to cross at the railroad bridge so that they may pass the quarantine inspection and disinfection treatment when necessary.

The location of the plant at the railroad bridge makes it more accessible for local persons desiring to leave Laredo by train to visit the plant and have their persons, clothing, and effects deloused in order to secure the certificate required by the transportation companies.

During the past year the treatment of infested passengers has been effected by utilizing the Mexican disinfecting plant at New Laredo, Mexico, and to some extent with the cooperation of State officials, disinfecting some persons at a small extemporized plant built at the footbridge by the local State quarantine officer.

Laredo has been closed to night travel during the entire fiscal year, this measure causing no active opposition.

The statistical data regarding the 14 cases of typhus fever that occurred at Laredo during the fiscal year is given later in this report, with the other cases. During November the officer in charge of supervision of border quarantine visited Brownsville in company with the supervising inspector of the United States Immigration Service along the Mexican border, with the intention of securing the cooperation of the Immigration Service in closing the international ferry between Matamoras, Mexico, and Brownsville, Tex., and requiring all persons entering from Mexico to cross at the international foot and railroad bridge.

This measure was found to be impracticable for the reason that no company or individual could be found who would erect a suitable plant near the railroad bridge, but the construction of a plant convenient to the ferry could be arranged for without further delay. As it was impossible to acquire title to a suitable site, an arrangement was made with the Matamoras and Brownsville Bridge Co., who also own the ferry, to erect a disinfecting plant at the ferry, this building being of the same general type as the plant at El Paso and Eagle Pass. Construction of the building was started about January 1, but due to many unforeseen obstacles, it was not completed and ready for use until May 1, 1917, when it was placed in operation.

Prior to this time, similar regulations to those at El Paso were enforced at Brownsville closing the port to night travel from Mexico. Limited travel by means of official quarantine passes was permitted only at the international bridge, the ferry service being entirely discontinued after 7 p. m. This regulation aroused considerable opposition on the part of local residents of Brownsville and Matamoras, the social relations between these two towns being more intimate than at other points along the Mexican border. The regulation was therefore modified so as to peremit night travel at both the bridge and ferry. Passes permitting this travel were given to quite a large number of persons known to be residents of the two cities and not subject to quarantine disinfection.

No cases of typhus fever occurred in the Brownsville district during the fiscal year. It is believed that the low altitude of this region and the comparatively mild winter climate is conducive to personal cleanliness, thus removing the menace of permanent louse infestation among the peon class. Since the opening of the disinfecting plant, with the routine bathing of “locals” as well as immigrants, a considerable improvement in the personal appearance of those crossing from Mexico has been observed at this port, as well as along the entire border.

The port of Hidalgo, Tex., located about 60 miles above Brownsville, although 8 miles from a railroad on the American side, has for two years been a favorite port of entry for immigrants from adjacent portions of Mexico.

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Arrangements were made with a local resident of Hidalgo to build and equip a suitable disinfection station at this port, he work being completed during January, 1917.

Owing to the high price of coal at this station, a steam sterilizing apparatus was not installed at this point, and the hot-air sterilizer used during the previous fiscal year at Hidalgo has been continued in the service with satisfactory results.

The routine vaccination of all arrivals from Mexico, which is carried out at all border ports, has resulted in the almost total absence of smallpox in the vicinity of Hidalgo during this year-a fact that has been frequently commented upon by the local county officials.

No case of typhus fever has occurred at the port of Hidalgo during this fiscal year.

The Mexican Railroad from Monterey to Brownsville follows the course of the Rio Grande for approximately 70 miles west of Brownsville, so that in order to prevent Mexican immigrants from leaving the train and crossing into American territory at a point where no facilities for quarantine inspection and disinfection had been established, it was found necessary to locate such a station at Rio Grande City, Tex.

At this port a suitable site for the location of the service plant was secured from the War Department on the Fort Ringgold Reservation. A frame structure, in which provision is made for the bathing and disinfection of both sexes, was constructed and placed in operation March 1, 1917. The office space of this building is shared with the immigration inspector on duty at this port.

Prior to the erection of the service plant, both immigration and quarantine functions were carried on in tents. No special apparatus for the sterilization of clothing has been installed in the Rio Grande City plant, for the reason that travel at this port is comparatively light, and such persons as are found to be infested with vermin have their clothing treated by submersion in gasoline.

If no facilities were available for the enforcement of the border quarantine regulations at this port, it would probably result in large numbers of Mexican immigrants leaving the train at Mier, Mexico, and crossing at this point in order to avoid the restrictions to which they would be subjected at either Hidalgo or Brownsville, should they continue their journey to either of those ports.

No cases of typhus fever occurred in the vicinity of Rio Grande City during the fiscal year.

COLUMBUS, N. MEX., TEMPORARY PORT.

Upon the withdrawal of the United States Army from Mexico a large number of refugees accompanied the soldiers on their march to the border. In order to handle this unusual situation, Columbus, N. Mex., was made a temporary port of entry, and a service officer was detailed to make the medical inspection of these refugees and to carry out the necessary quarantine measures.

This work covered a period of one week, from February 1 to 7, 1917, during which time 2,749 persons were inspected for disease, vermin infestation, and evidence of immunity against smallpox; 250 of these refugees were found to be vermin infested and were deloused, and 1,010 were vaccinated by the service officer, in addition to 550 who were vaccinated by officers of the Medical Corps, United States Army. No case of quarantinable disease was found, although several persons were temporarily held on account of suspicious illness. The Army officials had charge of the camp in which the refugees were detained, and furnished all necessary guards and Hospital Corps men to aid the service officer in carrying out this work. Medical officers of the Army loaned a sterilizing outfit and gave their cordial support to enforcing the necessary quarantine restrictions.

Statistical data of quarantine transactions at the Texas-Mexican border points for the fiscal year ending June 30, 1917.

1 Approximated. Strict account was not kept of the "locals" crossing the international bridge at El Paso. 2 Since opening of the disinfecting plant at Brownsvi le.

DESTRUCTION OF RATS ON VESSELS.

The fumigation of incoming vessels for the purpose of destroying rats has been continued as in former years. The number of rats so destroyed exceeded 18,550, the unknown cases representing those that were not recovered subsequent to fumigation, the omission of search being due to various circumstances. Not infrequently a fumigated vessel leaves port immediately on completion of fumigation, and before the clearance of fumes from the compartments. At other times when vessels are fumigated with cargo aboard subsequent search by the fumigators is only partially successful, as members of the crew are rather prone to throw the recovered carcasses overboard or burn them in furnaces.

For the most part the species of rats destroyed by fumigation were the Mus rattus and Mus alexandrinus, very few Mus norvegicus being reported. It is interesting to note that of 6,072 rodents destroyed at the city of New Orleans through the fumigation of vessels 5,997 were of the two species, alexandrinus and rattus, and only 10 were Norway rats, the remaining 65 being bandicoots and various species of wood rats.

In addition to the fumigation of vessels for the destruction of rats and mosquitoes, owners and agents not infrequently request this treatment for the sake of destroying bedbugs and other vermin about the vessel.

The agents used at the various stations were cyanide gas and sulphur dioxide, the latter in the strength and duration of exposure as provided in the quarantine regulations; the former in the proportion of 5 ounces of cyanide to 1,000 cubic feet of space and duration of exposure varying from hour for small, above deck compartments, to 14 hours for holds. The standard for fumigation by cyanide gas of 5 ounces per 1,000 cubic feet of space, with exposure for 1 hour, as provided in bureau circular of October 30, 1915, is purely a tentative one, and undoubtedly will be altered after more prolonged observation of the practical results obtained.