RETE MUCOSUM. 335 



culty, the history of a woman whose skin became black in the 

 period of a night, in consequence of a strong moral impression. 

 This woman had seen her daughter throw herself out of the win- 

 dow with her two little children; and we have since had occa- 

 sion to see, also, a woman, who having escaped capital punish- 

 ment, in the revolution, had experienced the same accident. The 

 latter was at the period of menstruation when she learned this 

 news. The menses were immediately suppressed, and from 

 white, which she was, she became black as a negress, which 

 colour continued even to her death. We dissected with care 

 the skin of these two women, and found the coloured portion to 

 be the rete mucosum. We found it sufficiently easy to isolate 

 the epidermis and the dermis, which presented no abnormal co- 

 loration. This black colour must be the result of a sanguineous 

 exhalation which operates upon the rete mucosum. 



" The violet tinge of the skin is, ordinarily, the result of em- 

 barrassed circulation. The skin becomes blue in many very ad- 

 vanced diseases of the heart. The name of Cyanosis, or blue 

 disease, has been given to this colour of the skin, which is falsely 

 attributed to an immediate communication of the auricles by 

 means of the unobliterated foramen ovale. This cause of the 

 cyanosis is much more rare than is commonly supposed."* 



The pigment of the rete mucosum would seem, for the fore- 

 going reasons, to be continually undergoing a deposition and ab- 

 sorption. When it has been lost by a blister in an African, it 

 is generally restored in a short time afterwards: the same oc- 

 curs in their cicatrices, but requires a longer period. The ob- 

 servations of chemists tend to prove that it is formed principal- 

 ly by carbon. Its apparent use is to defend the skin from the 

 rays of the sun, in illustration of which several ingenious ex- 

 periments have been executed by Sir Everard Home.f 



The influence of the continued use of nitrate of silver, in 

 giving a lead colour to the skin is well known. Anatomists 

 generally have rejected the idea of the vascularily of the rete 

 mucosum, yet it would seem to have been injected, on one oc- 

 casion at least by the late Dr. Baynham, in a leg which was 



* Cours de Medecine Clinique, par Leon Rostan. Paris, 1830. 

 f Philos. Transact. London, 1821. 



