DERANGEMENTS OF SECRETION IN THE SKIN. 519 



it contains. The composition and source of other substances, which 

 sometimes appear in the sweat and which likewise stain the linen, are 

 unknown. In a few instances of suppression of urine, trustworthy 

 observers have discovered crystals of urea upon the skin. 



In some persons, the sebaceous secretion of the skin is so much 

 increased that the hair and cutaneous surface, especially that of their 

 face, always shines as if it had been freshly anointed with pomade or 

 grease. In others it is so deficient that, unless replaced by an un- 

 guent, the skin and hair are always dry, dingy, and disposed to crack. 

 The former condition is most likely to exist in persons with an exube- 

 rance of fat throughout the entire body ; the latter in individuals with 

 little fat, or in those who are suffering from wasting disease. 



Qualitative changes in the sebaceous secretion are often observed, 

 in which the unctuous matter of the skin does not remain liquid, but as- 

 sumes a more solid consistence. Barensprung believes that the in- 

 creased solidity of the cutaneous secretion is due in part to a prepon- 

 derance of solid fat, and in part to an admixture of a larger amount of 

 cast-off glandular epithelium. The increased solidity of the sebaceous 

 matter of the skin is usually accompanied by exuberance in its quantity, 

 thus in some measure justifying the name seborrhoea, applied to a con- 

 dition of the skin in which it is covered with crusts of dry sebaceous 

 matter. Seborrhcea is most frequently observed upon the scalps of 

 infants, where the inspissated secretion, rendered brown by admixture 

 of dust, often forms scaly crusts of nearly a line in thickness, of which 

 superstition forbids the removal ; and it is not until the second year, 

 when the scabs are lifted from the scalp by a freer growth of the hair, 

 that they break up into separate scales, and are removed as such with 

 a comb. Many a case of the so-called pityriasis capitis, in which there 

 are many white scales, some of which adhere to the skin, some stick- 

 ing to the hairs, while still others are sprinkled upon the clothing, are 

 the result of seborrhcea. Microscopic examination, by which it is found 

 that the scales contain numerous oil-globules, affords the best means 

 of distinguishing this form of seborrhcea from a dry eczema capillitii. 

 Finally, thick crusts of sebaceous matter, browned by admixture with 

 dust, and whose surface is generally broken up into numerous blocks, 

 appears upon the cheeks, nose, eyelids, ears, and nipples, as well as 

 upon other parts of the skin where a copious lanugo prevents the fall 

 of the crusts. Abnormal secretion of sebaceous matter may go on so 

 rapidly, that the cast-off scabs are speedily replaced by new ones, 

 which greatly disfigure the patient, who is usually a female suffering 

 from menstrual derangement (ichthyosis sebacea, Rayer). Thick, hard 

 crusts of sebaceous matter are to be softened with liquid fat, and then 

 removed with caution, since the epithelial coat beneath them is ex- 

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