: 



CUTANEOUS EXHALATION. 419 



exhalation from the lungs is not influenced by the external tempera- 

 ture, but only by the degree in which the surrounding air is previously 

 saturated with moisture. 



746. The variations in the amount of fluid set free by Cutaneous 

 and Pulmonary Exhalation, are counterbalanced by the regulating 

 action of the Kidney ; which allows a larger proportion of water to be 

 strained off in a liquid state from the blood-vessels, as the Exhalation 

 is less, and vice versd. The Cutaneous and Urinary excretions seem 

 to be vicarious, not merely in regard to the amount of fluid which they 

 carry off from the blood, but also in respect to the solid matter which 

 they eliminate from it. It appears that at least 100 grains of effete 

 azotized matter are daily thrown off from the skin ; and any cause 

 which checks this excretion, must increase the labour of the Kidneys, 

 or produce an accumulation of noxious matter in the blood. Hence 



.ttention to the functions of the skin, at all times a matter of great 

 importance, is peculiarly required in the treatment of Urinary diseases ; 

 and it will be often found that no means is so useful in removing the 

 lithic acid deposit, as copious ablution and friction of the skin, com- 

 bined with exercise. When the Exhalant action of the skin is com- 

 pletely checked by the application of an impermeable varnish, the effect 

 is not (as might be anticipated) an elevation of the temperature of the 

 body ; on the contrary it is lowered, in consequence, as it would appear, 

 of the interruption to the aeration of the blood through the skin, which 

 is a function of such importance in the lower animals ( 671), and of 

 no trifling account in Man ; and in a short time, a fatal result ensues. 

 A partial suppression by the same means gives, rise to febrile symptoms, 

 and to Albuminuria, or escape of the albuminous part of the liquor 

 sanguinis into the urinary tubes, in consequence (it would appear) of 

 the increased determination which then takes place towards the Kid- 

 neys. These facts- are interesting, as throwing light upon the febrile 

 disturbance which accompanies those cutaneous diseases that affect the 

 whole surface of the skin at once, and interfere with its functions ; and 

 as partly accounting also for the Albuminuria which frequently mani- 

 fests itself during their progress, especially in Scarlatina. 



747. The Skin is likewise furnished with numerous Sebaceous glands, 

 which are distributed more or less closely over the whole surface of the 

 body ; being least abundant where the Perspiratory glandulae are most 

 numerous ; and vice versd. They are altogether absent on the palms of 

 the hands and the soles of the feet ; and are particularly frequent in the 

 skin of the face and in the scalp. They differ greatly in size and in de- 

 gree of complexity ; sometimes consisting of short straight follicles ; some- 

 times closely resembling the Sudoriparous glandulae, the tubes, however, 

 being usually straighter and wider ; and being sometimes much more 

 complex in structure, consisting of a number of distinct sacculi clustered 

 around the extremity of a common duct, into which they open, and form- 

 ing little arborescent masses about the size of millet-seeds. In some situa- 

 tions they acquire still greater complexity. Thus the Meibomian glan- 

 dulae, which are found at the edges of the eyelids, and which secrete an 

 unctuous matter for their lubrication, are long sacculi branching out at 

 the sides (Fig. Ill) ; and the glandulae of the ear passage, which secrete 



