DIFFUSION OF WATER THROUGH DEAD PLANTAR, PALMAR AND
`TORSAL HUMAN SKIN AND THROUGH TOE NAILS
`
`GEORGE E. BURCH, M.D.
`AND
`TRAVIS WINSOR, M.D.
`NEW ORLEANS
`
`Since the observations of Erismann 1 in 1875
`on tile rate of diffusion of v~ater through the
`skin of breasts and palms, studies .of diffusion
`through dead human skin have been neglected
`and the rate of diffusion through toe nails has
`not been studied. In the study of insensible
`loss of water through the body and especially
`through the skin, it is important to know the
`relative ratio of water loss by diffusion through
`the skin of various portions of the body and
`nails.
`
`~¢IATERIALS AND METHODS
`
`The rate of diffusion was measured for dead skin
`collected from bodies within a few hours (one to twenty-
`four, usually three to four) after death. Only healthy-
`looking skin of well nourished nonedematous bodies
`was used. The skins were collected from the following
`areas of separate bodies: epigastrimn of 9 different
`bodies, axillas of 5, plantar surfaces of 10, palms of 3,
`and nails of the big toe of 5 others. In most instances
`several samples of skin and nail were collected from
`the same body. The causes of death of subjects varied
`considerably, including cerebral hemorrhage, accident
`(automobile), pneumonia, hepatitis, postpartal sepsis and
`chronic pulmonary tuberculosis. Occasional toe nails
`and plantar skin were collected from amputated feet.
`The skins and nails were brought to the laboratory
`and mounted oi1 a brass cylinder as shown in figure 1.
`The skin or nail was carefully prepared by the removal
`with surgical scissors of all fat, fibrous tissue and other
`subcutaneous and subungual tissue, leaving a relatively
`clean under surface. The skin or nail was then cut
`to cover the opening of the cylinder. It was then placed
`over the opening of the cylinder (e) which contained
`loose cotton and was filled with isotonic solution of
`sodium chloride. This solution filled the cylinders so
`that the fluid rested against the deep surface of the skin
`or nail. The cotton below provided means for the
`solution to keep in contact with the skin at all times,
`even with a decrease in the volume of fluid with evap-
`oration. A brass ring (b) covered with a film of stop-
`cock grease on the surface which came into contact
`with the skin was placed over the skin. Two pins
`soldered to the ring, 180 degrees from each other, were
`
`This is the seventh report from this Laboratory on
`Tropical Physiology.
`From the Department of Medicine, Tulane Univer-
`sity Medical School and Charit3y Hospital.
`Aided by a grant from the Rockefeller Foundation
`and the Hells Institute for Medical Research.
`!. Erismann, F.: Zur Physiologic der Wasserver-
`dunstung yon der Haut, Ztschr. f. Biol. 11:1, 1875.
`
`slipped into loose-fitting holes properly placed in the
`top of the cylinder (e). These pins prevented the brass
`ring and skin from twisting when the cap was screwed
`into place. The threaded portions were greased with
`stopcock grease. This tightly sealed a diaphragm of
`skin or of nail of 2 sq. cm. in area over the brass cylin-
`der. This permitted loss of water only by diffusion
`through this known surface area of the skin or nail.
`Once the section of skin was in place the seal was kept
`intact, and the skin was not touched throughout all
`subsequent weighings. The skin or nail mounted on
`the cylinder was placed in a room brought to the
`desired temperature and relative humidity and allowed
`
`A B
`
`Fig. 1.--A diagram of the brass cylinders used for
`the measurement of the diffusion of water through dead
`skin. See text for details.
`
`to dry for two to three hours. The metal cylinder with
`the tissue in place was weighed on an analytic balance
`to an accuracy of 0.1 rag. After a period of from a few
`minutes to twenty-four hours, usually four to five hours,
`the unit was weighed again. This was repeated several
`times for at least two successive days. Any loss in
`weight represented water lost by diffusion through the
`skin or toe nail. The temperature and relative humidity
`of the room were varied to produce a cool comfortable
`room or a hot and uncomfortable one. The abs61ute
`values of these are shown in figure 2. Some of the cylin-
`ders with skin or nail mounted in place were put in front
`
`39
`
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`ARGENTUM EX1027
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`40
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`ARCHIVES OF DERMATOLOGY AND SYPHILOLOGY
`
`of an ordinary electric fan at the various room tempera-
`tures and humidities in order to learn the influence of
`air currents on the rates of diffusion.
`Some cylinders were filled respectively with whole
`blood, isotonic solution of sodium chloride and dis-
`tilled water, with their surface exposed directly to
`the atmosphere.
`In another study a piece of intact epigastric skin
`was placed over the cylinder and studied as previously
`described. Its corneous layer was then removed by
`gentle scraping and the rate of diffusion restudied.
`One area of epigastric skin was observed continuously
`for sixty-one days under varying room conditions.
`
`diffusion of water as well as did an increase in
`temperature. A change in the humidity of the
`atmosphere did not produce as pronounced an
`influence on diffusion as did changes in tempera-
`ture or air currents. An increase in the humidity
`of the air decreased the rate of diffusion.
`Diffusion of water occurred much more rapidly
`through epigastric skin with its corneuln re-
`mov,~d than through intact skin (fig. 2). The
`rate was much more rapid from uncovered whole
`blood, isotonic solution of sodium chloride and
`
`Epi~astrtum Axtlla 6oleo[hot Toenail ~Palmdhard ’~ ~’~ ~-P~’
`Ep~¢r,um mum. blood ~al= u~
`Fig, 2,--The rate of diffusion of water measured at various room conditions through skin from various
`portions of the body, including toe nails and intact epigastrlc skin immediately before and after denudation
`(removal of the corneum) and also from uncovered surfaces of fluids. The rate of diffusion of water through
`the epigastrlum and the uncovered surfaces of fluids shown to the left of the figure were measured simultane-
`ously under similar room conditions.
`
`Many observations were made of each skin or nail
`for each room condition. Several hundred measure-
`ments were made in all, much too many to be presented
`in detail.
`
`RESULTS
`The results are summarized in figures 2 and 3.
`The absolute values are shown in the figures.
`The rate of diffusion of water through the epi-
`gastric skin was found to be much slower than
`that through any of the other skins or the toe
`nail. Diffusion of water took place most rapidly
`through the skin of the plantar and palmar sur-
`faces. It occurred through the toe nail at a rate
`about equal to that through the plantar and
`palmar skins. Fanning increased the rate of
`
`4
`
`@
`
`(75! 1E¢- ~5±5X)
`
`Fig. 3.--Variations in the rate of diffusion of water
`through a sample of skin from the epigastrium studied
`continuously for sixty-one days. The room conditions
`were: temperatures, 24 ± 2 C., and relative humidity,,
`69.2 ± 20 per cent.
`
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`BURCH-WINSOR--DIFFUSION OF WATER THROUGH SKIN AND NAILS
`
`41
`
`distilled water (these fluids are listed in an
`ascending order of the rates of diffusion of
`water) than through epigastric skin (fig. 2).
`Figure 3 shows the influence of time on the
`inhibiting influence of skin to diffusion of water
`through it. The rate of diffusion changed little
`for the first two weeks; then it increased about
`three times, remaining at this level for the next
`six weeks. The rate of diffusion of water
`through this skin was still much slower than
`that through fresh plantar and palmar skin, toe
`nails or the aforementioned uncovered fluids even
`sixty-one days after death.
`
`The observations indicate the great faculty
`possessed by human skin to inhibit diffusion of
`water. This is in keeping with observations in
`previous studies.~- This property resides mainly
`in the corneum, as shown again in these studies.
`The cylinders containing whole blood, isotonic
`solution of sodium chloride and distilled water
`lost water at a rate greater than three hundred
`times that through epigastric skin.
`The greater rate of water loss by diffusion
`through skin of the palms, soles and the toe
`nails is difficult to explain. The chemical and
`the histologic constitution of the entire skin and
`of the corneum, in particular of the palms and
`soles, are different from those of epigastric skin.
`How such differences might explain the striking
`differences in the rates of diffusion of water is
`unknown. The relative proportions of alpha
`and beta keratin in these tissues has not been
`determined; in fact, the physicochemical nature
`.of skin is a much neglected aspect of biochemis-
`try. The more rapid rate of diffusion of water
`
`2. (a) Burch, G. E., and Winsor, T. : Rate of Insen-
`sible Perspiration (Diffusion of Water) Locally
`Through Living and Through Dead Human Skin, Arch.
`Int. Med. "/4:437 (Dec.) 1944. (b) Winsor, T., and
`Burch, G. E.: Differential Roles of Layers of Human
`Epigastric Skin on Diffusion Rate of Water, ibid. 74:
`428 (Dec.) 1944.
`
`through the skin of the palms and soles probably
`keeps these areas of skin slightly moist, thus
`facilitating the grasping of objects and walking.
`The difficulty one has in grasping objects
`securely when the palmar skin is dry is well
`known.
`The epigastric skin studied for sixty-one days
`showed the prolonged efficiency of dead skin in
`the inhibition of diffusion of water. The fact
`that it changed little, even though pronounced
`digestive changes were noted in the underlying
`layers while the corneum merely wrinkled, is
`further proof that the corneum is the layer
`mainly responsible for the inhibition of the dif-
`fusion of water. The corneal layer is composed
`of dead cells even in intact living skin and
`therefore changes relatively little for several
`weeks after death. This layer has also been
`shown to be mainly responsible for the inhibition
`of diffusion of water in living intact skin.2u
`The applications of these findings in health
`and in disease are obvious.
`
`CONCLUSIONS
`
`Our data support the following conclusions:
`1. Diffusion of water occurs least rapidly
`through the skin of the epigastrium, most rapidly
`through the skin of the palms and soles and at
`a moderate rate through the skin of the axilla.
`2. The rate of diffusion of water through the
`toe nail is essentially the same as that through
`the skin of the palms and soles.
`3. Skin is an excellent barrier to the diffusion
`of water from the body, the corneum being the
`principle inhibiting layer.
`4. Increases in temperature or air currents
`are especially effective in increasing diffusion,
`while changes in humidity of the air influence
`the rate of diffusion to a less extent.
`5. Skin will retain its inhibiting influence on
`diffusion for many days (at least sixty-one days)
`after death provided the corneum remains intact.
`We were assisted in these studies by M. G. Morgavi.
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