THE HYPERKERATOSES 



2265 



The slight development of lanugo hair is the cause, as noted by 

 Fox, of the peculiar velvety feeling of the negro skin. 



The most important characteristic of the skin of tropical native 

 races is the dark pigmentation. It is said that this pigmentation 

 is not present at birth, but develops within a few hours to several 

 days after birth. In our experience, it cannot be doubted that at 

 the time of birth in many cases the babies present a much lighter 

 colour than the adult people. The skin, however, is not whitish, 

 but of a muddy brownish colour, and darkens greatly within a few 

 days — in some cases is quite dark also at the time of birth. It is 

 said that the pigmentation increases till puberty, and then, after 

 remaining stationary during adult life, slowly decreases during old 

 age. The maximum pigmentation is found on the loins, posterior 

 portion of the trunk, shoulders, buttocks, and thighs; the least pig- 

 mentation is found on the prepuce, vulva, palms, and soles. In 

 some races the oral mucosa is not pigmented; in others there is a 

 patchy dark pigmentation which extends often to the tongue. The 

 dark patches on the tongue have been considered by several writers 

 to be a pathological condition, and a sign of ankylostomiasis. We 

 have observed such patches, however, in numbers of normal natives. 

 The hair is said to become white at a later date among negro races 

 than in Europeans; we have not noted any distinct difference, 

 either among them or the natives of Asia. 



It is said by some writers that native races, and especially the 

 negro African races, are less susceptible to pain than the white 

 man. In our experience there is hardly any difference in the 

 ordinary dolorific sensibility, but the thermic sensibility is probably 

 less. 



PYOGENIC INFECTIONS. 



These are very common in tropical countries. Impetigo and 

 Ecthyma lesions are frequently met with. The symptoms and 

 course are identical with what one finds in temperate zones, and 

 the treatment is the same — removal of the crusts, disinfection with 

 a lotion, such as a perchloride of mercury (i in 2,000), and dressing 

 with a white precipitate ointment (i per cent.). 



Boils. — This is a common affection in the tropics, very stubborn, 

 and difficult to cure. The quickest and most reliable method of 

 cure in cases of multiple boils is, in our experience, Wright's vaccine 

 treatment, the vaccine being prepared from staphylococci isolated 

 from the patient. When this treatment cannot be carried out, the' 

 administration of yeast preparations internally will be found to be 

 useful in some cases — -e.g., ceridin pills. Occasionally a small boil 

 may be aborted by applying a droplet of pure carbolic acid by 

 means of a pointed pencil of wood drilled into the centre of the 

 papule. For old indurated boils the continuous application of a 

 carbolic lotion (2 to 5 per cent.) on lint occasionally causes them to 

 become absorbed. 



