90 TRICIIOLOGIA MAMMALU'M : 



skin of a negro, if it has not been very stimulating, in twelve hours a thin, grey, trans- 

 parent membrane will be raised, under which is found a fluid. This membrane, (says 

 this author,) is the cuticle or scarf-skin; when this, with the fluid, is removed, the surface 

 underneath appears black. But, if the blister has been stimulating, another membrane, 

 in which this black color resides, will also be raised with the cuticle. This (he adds) is 

 the rete mucosum ; when this membrane is removed, the surface of the true skin comes into 

 view, and it is white, like that of an European. 



Mr. Flourens has also examined this subject. (See Annals di S'ci. Nat, t. vii., p. 156.) 

 He found four distinct layers between the cuticle and the cutis ; the second of which (he 

 says) is a mucous membrane, a distinctly organized body, underlaying the pigment and 

 existing in persons of dark color only. Mr. Flourens sought in vain for this membrane, 

 between the cutis and outer lamina? of the epidermis of a white man ; and yet this is the 

 seat of the discoloration produced in his complexion by exposure to the sun. 



From these examinations this distinguished naturalist and anatomist was able to pro- 

 nounce, definitively, that the discoloration in the skin of the white man is totally different 

 in kind from the cause of blackness in the negro, and he therefore concludes that the 

 negro and the European are SEPARATE SPECIES OF BEINGS. 



We might add, that Henle, having examined the skin of a negro, found, besides the 

 cells detected in the white man, others which contain a black pigment. (See Miiller's 

 Arch., 1840, Heft. 2, 180.*) We, therefore, feel ourselves authorised in inferring that the 

 coloring matter of the skin, and that of the hair of man are not identical. 







As TO THE LOWER ANIMALS. :How this question is to be determined in regard to the 

 hair and skin of the lower animals will, perhaps, depend upon other considerations ; for 

 while we find the blackest hair of the head of our species issuing out of a fair skin, we 

 are credibly informed that the colored spots or portions of the hair of the lower animals, 

 generally, if not always, correspond with a similar tint of the skin. Hence we find authors 

 coupling these two integuments together. Mr. Youatt, who tells us that he composed the 

 3d chapter of his book with the assistance of several eminent gentlemen, whom he names, 

 says therein that, in regard to sheep, the color of the skin and probably that of the hair 

 and wool also, is determined by the rete mucosum ; or, at least, the hair and wool are of the 

 same color as this substance. (See Lib. of Usef. Know., p. 52,) And it must be borne in 

 rnind, that the coloring matter of & per feet hair, (i. e. of the head of the oval-haired man,) 

 is confined to a central canal, while the coloring matter of the hair and wool of the lower 

 animals, so far as our experience goes, is disseminated in the cortex and intermediate 

 fibrous substance, or in the cortex alone. 



4th. Is the color of the hair ever influenced by accidental, external or temporary causes? 

 It is said in the Lond. and Edin. Jour, of Med. Sci., for 1841, p. 596, that the writer has 

 a hair taken from the skin of a native New Zealander, whose face was closely tattooed, and 



* P. Barnard, Prof, of Physiology, in Paris, says that the hair contains pigment grains but no pigment cells. (2CG Cour. 

 Physi., 1848. 



