IN THE HUMAN SPECIES. 235 



defying calculation by the number and fineness of its tubes. 

 In the glow of exercise or the flush of shame, in the excite- 

 ment of fever, or the eruption of measles, scarlatina, &c. 

 these cutaneous vessels are filled with blood ; they may be 

 injected with coloured fluids after death. Tlieir ramifica- 

 tions are particularly numerous and subtle in those parts of 

 the cutaneous organ which possess the most exquisite sen- 

 sibility; and where the surface is found, on minute exami- 

 nation, to be covered by numerous fine processes called 

 papillae or villi*. 



The absorbents of the skin seem nearly equal in number 

 to its blood-vessels. 



Numerous nerves enter it in all parts, and distribute 

 their largest ramifications in the situations occupied by the 

 papillae. 



The colour of the cutis is uniform, or very nearly so, in 

 all the varieties of the human race, and depends entirely on 

 the state of its capillary blood-vessels. According as they 

 are full or empty, it may vary (as we see in the white races) 

 from a more or less florid red, constituting what artists call 

 flesh-colour, to the waxy paleness of fainting or exhaustion 

 from haemorrhage. Maceration in water makes its areolar 

 tissue quite white; and injection with size coloured by 

 vermilion gives it a deeper or lighter shade of red, ac- 

 cording to the force employed. 



The cuticle or epidermis, the exterior layer of our com- 

 mon integuments, is the thin transparent or light grayish 

 pellicle raised by a blister : in the natural state it adheres 

 closely, almost inseparably, to the subjacent parts, and Is 

 accurately fitted to the cutis, having folds and lines corre- 

 sponding to all the inequalities of that organ. It presents 

 no traces of fibres, laminae, or cells ; it has no blood-vessels, 



* The external vascular surface of the cutis, with its papillae or villi, seems 

 to be what Bichat has described as a separate stratum, under the name of 

 corps reticulaire. {Jnat. Generale.) I have never seen the distinction. My 

 object here is not, however, to describe the skin fully, but merely to consi- 

 der it as the seat of colour. They who wish for further information on the 

 structure of the integuments may consult Dr. Rees's Cyclopaedia, art. In- 

 teguments ; and Dr. Gordon's System of Human Anatomy, book ii. chap. 4. 



