UNIVERSAL POROSITY. 259 



namely, the large perspiratory ducts, whose orifices may be seen as 

 little clottings on the wavy ridges at the ends of the fingers ; the 

 sebaceous follicles which anoint the skin with a thin limpid oil that 

 prevents the excessive evaporation of watery moisture ; and the pas- 

 sages which lodge and transmit the hairs. All these are channels 

 of communication for influences, that is to say, influential sub- 

 stances, from the body to the world, and vice versa. They are 

 simple involutions of the skin upon itself, or portions of its three 

 layers as it were pushed deeply inwards, and the end of the tube so 

 intruded, wound upon itself into a little bail in the perspiratory 

 pores and sebaceous follicles; whilst in the hairs on the other hand, 

 the tube is formed as before, but the cuticle at the bottom of it 

 grows into a prolonged cylinder that comes out again through the 

 orifice ; the hair being essentially a linear extension of the cuticle. 

 All these organs, viz., the perspiratory glands and ducts, the seba- 

 ceous follicles, and the hairs, in the channels of which latter the 

 sebaceous follicles frequently open, are beset with little blood-vessels; 

 and as the matters given out and taken in, either come from, or go 

 to, the blood, so the exterior pores are but the outer porticoes to the 

 real pores that lie in the sides of the blood-vessels. The porosity 

 of the outer skin is the sign of a universal porosity in the system, 

 whereby, according to circumstances, everywhere leads to every- 

 where.* 



The offices necessarily performed by the skin as the frontier of 

 the body, consists in the purification of the system, in the elimina- 

 tion cf some of its products, and in its renovation by fresh substances, 

 all under the auspices of the sense of touch. We will now regard 

 it by the light of this threefold function. And first, for the office 

 of 'purification. 



This is effected by the entire surface of the body, which is con- 

 tinually giving off an atmosphere of exhalations, differing in quantity 

 as well as grossness at different times. It is calculated by an inge- 



* The same muscles which produce action without, and carry us along our 

 way, shape and alter the ways and channels within, determining the fluids be- 

 tween new embankments of substances in action; and the possibility of these 

 constant changes in the organism, whereby every action makes its own facilities, 

 is due to the porous cooperation of the skin man. 



