A study of chronic mercurialism in the hatters' fur-cutting industry / From the Division of Industrial Hygiene, Senior Surgeon R.R. Sayers, medical officer in charge. Medical studies by: Paul A. Neal, P.A. surgeon, Roy R. Jones, P.A. surgeon. Engineering studies by: J.J. Bloomfield, P.A. sanitary engineer, J.M. Dallaville, P.A. sanitary engineer. Statistical analysis by: Thomas I. Edwards, technical editor. Prepared by direction of the Surgeon General.

  • United States. Public Health Service.
Date:
1937
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    4) time. It has been in use for some time for detecting minute amounts of mercury vapor in the air and has an extremely high sensitivity. In the present study, mercury-impregnated dust was excluded from the detector by placing a single-thickness Whatman paper thimble at the point where air enters the instrument. The dust-free air then passed into the device, was preheated to a temperature of 70° C., and then allowed to come in contact with paper coated with active selenium sulphide. When mercury vapor comes in contact with the paper it is blackened to a degree which is dependent on duration of exposure and the concentration of mercury. The amount of mercury vapor in the air can be determined by comparing the sample obtained with standards which accompany the instrument. In order to determine the amount of mercury-impregnated dust in the air, samples were obtained with the impinger apparatus (3). Since it was found in preliminary observations that the mercury- coated fur was greasy, and hence difficult to wet, it was necessary to use a 25-percent alcohol and water mixture as a collecting medium. Samples thus obtained were shipped to the central laboratory in Washington, where they were analyzed by Associate Chemist F. H. Goldman by means of the electrolytic method described by Fraser (2).! The konimeter was employed for the determination of the amount of dust to which workers were exposed (5). In the control studies which followed, certain ventilation measurements were made on the exhaust systems employed. These readings were obtained with the Pitot tube. 1 Since preliminary treatment of such samples is necessary before Fraser’s method can be applied, a brief description of the procedure follows. The sample was transferred to a 500 ce Kjeldahl flask, and the alcohol was boiled off very rapidly for 5 to 10 minutes. After cooling, 10 cc of concentrated sulphuric acid was added and then 4 g of potassium per- manganate. The neck of the flask was washed down with water. The sample was-allowed to digest at a temperature just under the boiling point for 2 hours. It was then decolorized with oxalic acid.crystals {about 3 g are required), warming if necessary. Unless the solution is cold, it is better to add the oxalic acid in small amounts during this operation. The solution was next transferred from the Kjeldahl flask to a 250 ce glass-stoppered Erlenmeyer fiask, 1 ce of 0.5 percent copper sulphate solution was added, and then H2S was passed in for about one-half hour. The precipitate was allowed to stand overnight and then washed by centrifuging. Chlorine gas was then passed into the centrifuge cup containing the copper and mercury sulphide precip- itate after the addition of 5 cc of water. Solution was usually effected in 15 minutes, after which air was passed through to remove the chlorine. This solution was transferred to a 50-cc beaker, 2 cc of saturated oxalic acid and & cc of saturated ammonium oxalate were added. The mercury was plated out using a pure gold cathode 1 by 3 cm and 4 mm thick. The voltage was kept at 1.3-1.5 and the time was 18-24 hours. Theanode was platinum. The gold electrode can be easily made in the laboratory. A piece of gold foil is cut to the specified dimensions and is welded to a platinum wire by heating wire and foil in position on an anvil with a Bunsen flame, finally tapping gently with asmall hammer. Care must be taken not to melt the gold by excessive heating. The electrode which has the mercury and copper plated out on it was washed in water, alcohol, and ether successively, and was then weighed on a micro-balance. After weighing, it was placed in a Pyrex combustion tube through which a stream of hydrogen was passed. The tube was heated carefully and the mercury was driven off. After cooling, the electrode was again weighed and the mercury determined by difference. 129152—37——-2
    Preparation of Hatters’ Fur The processes used in the manufacture of hatters’ fur may be roughly divided into three parts: First, the preparation of the pelt; second, the carroting and drying of the fur; and third, the cutting or shearing of the hair from the skin. These constitute the basic steps in all hatters’ fur establishments. Such differences as may be found to exist among various plants pertain chiefly to the degree to which some departments have been mechanized. DESCRIPTION OF OPERATIONS AND OCCUPATIONS Types of pelts used.—Practically all the hatters’ fur used today is obtained from the pelts of rabbits or hares. The dry, raw pelts, turned inside out, are shipped in bales containing approximately 200 dozen. Most of these pelts are shipped from Great Britain, France, Australia, Belgium, and Russia. Relatively few pelts are produced in this country for the hatters’ fur industry. Small amounts of furriers’ waste or scraps of pelts from muskrats, squirrels, hares, etc., are also utilized. These yield felts with finer textures and are used in making high-grade felts. Disinfecting.—As a rule, all the skins shipped are packed in naph- thalene or other suitable preservative. In some instances, however, especially when scraps and inferior grade skins are used, it is necessary to eradicate worms which infest the hides. In such instances, the skins are placed in large containers into which hydrocyanic acid gas is introduced under pressure. The. worms are killed after a short exposure to this gas. Arsenic, which was formerly widely used for the preservation of skins, no longer appears to be employed in baled pelts. : , Drumming and cleaning.—The baled pelts are exceedingly dry and brittle, and must be carefully handled to avoid the loss of good skins through breakage. To condition the skins for the handling to which they will be subjected, as well as to clean them, they are placed in large revolving drums containing dampened sawdust and sand, which are rotated for approximately 60 minutes. The pelts are then trans- ferred to cylindrical screens which are rotated to remove the sawdust and sand and to dry the pelts. (See fig. 2.) Opening.—When the pelts have been conditioned, they are delivered to the openers, who mount each pelt on an upright wooden fork and cut off heads, tails, and legs, and slit the hide. This work is usually done by girls. (See fig. 3.) Clipping.—The opened pelts are counted and sorted according to quality and color. They are then taken to the clippers for shearing the long coarse hairs which are undesirable. Clipping consists of placing the skins on a small iron rail which, when pushed forward,
     FIGURE 2.—CLEANING SCREEN FOR PELTS RECEIVED FROM DRUMMER.
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