IN THE HUMAN SPECIES. 237 



licate quite impossible, to exhibit it detached, in any consi- 

 derable portion, as a distinct membrane. It agrees with the 

 cuticle, in shewing nothing like fibrous texture ; in being 

 inorganic and extravascular. It diffuses itself in water, and 

 communicates a turbid cloud to the fluid like that produced 

 by the pigmentum nigrum of the eye; then subsides, as an 

 impalpable powder, to the bottom. Thus the source of colour 

 in the dark varieties of our species is satisfactorily ascertained. 

 I have stated elsewhere that '*' the demonstration of this 

 reticular body is much less easy in the white races than in 

 the Negro ; and indeed very little seems to be known con- 

 cerning its anatomy in the former;" and further, " that it 

 seems really to be a matter of doubt, whether in the white 

 races there be any colouring matter in the exterior capillary 

 system analogous to the black substance of the Negro, or 

 whether the colour of their surface arise merely from that 

 of the cutis and cuticle*." When the cuticle separates by 

 putrefaction from the cutis, the surfaces are moistened by a 

 putrid offensive fluid : but I could never detach any thing 

 like a distinct membrane, even in the smallest portion f. 

 The late Dr. Gordon came to a similar conclusion, from 

 his investigation of the subject. " After the strictest exami- 

 nation, I have not been able to find any light-coloured rete 

 mucosum, corresponding to this black one, in the inhabi- 

 tants of Great Britain, nor in those of other nations resem- 

 bling them in colour. I have tried all the means usually 

 said to be necessary for discovering it, and many others 

 besides, but always without success : I am, therefore, dis- 

 posed to deny the existence of any such membrane in white 

 persons ;{:." 



* Rees's Cydopccdia, art. Integuments. 



+ SoEMWERRiNQ remarks that lie once found, in an European female, the 

 outer covering of the cutis distinctly visible into two lamellae ; and that he 

 preserves a specimen of it in his collection. Ueh. die Korperliche Vcrschie- 

 denheit, &c. p. 45. 



+ System of Human Jnaiomy ; v. i. p. 242. I cannot omit this opportu- 

 nity of paying to my deceased friend the small but sincere tribute of my high 

 respect, and deep regret for the loss which our science has sustained in his 

 premature death. His abilities, acquirements, and zealous devotion to 



