124 



GENERAL ANALYSIS. 



466. THE KIDNEYS MAY ALSO SERVE the purpose of 

 Eliminating Water when removed for the purpose of 

 diminishing the volume of "the circulating fluid, especially 

 as the earthy substances Eliminated by them will require 

 a considerable quantity of fluid to float them away. 



467. WHEN WATER is ELIMINATED FOR THE PUR- 

 POSE OF COOLING THE BODY it must be exposed to evapo- 

 rate from an extensive surface, such as is afforded only 

 by the Skin ; so that the proper organs must be located 

 in the Skin, where the perspiratory glands are placed. 



FIG. 109. 



Fig. 109 represents a rery highly mag- 

 nified view of a perpendicular section of 

 a small portion of the Skin. It is divided 



M into three parts : 1, the external layer or 

 cuticle, composed of cells starting up from 

 the basement membrane below, and grad- 



i& ually becoming dry and flattened scales 

 as layer after layer they approach the sur- 

 face, from which they are worn or drop 

 off. Two curved passages, the outlets of 

 the perspiration, are noticeable, commu- 

 nicating below with four tubes in one case, 

 and two in the other, that are coiled at 



r their lower extremities, and form the per- 



\g spiratory glands, g. 2 is the papillary 

 portion in which the nerves of touch com- 



\a mence, surrounded by a network of lym- 

 phatics and capillaries, supplied through 

 a, an arterial branch. 3 is the true skin 

 composed of sinewy fibres woven around 

 the tubes, nerves, and perspiratory glands. 

 In the lower part the meshes are larger, 

 and filled sometimes with clusters of fat- 

 cells, as at e. 



468. ANY VISCID SUBSTANCES that may not with 

 propriety be Eliminated by the Kidneys, the Digestory 

 Canal, nor by its appendages, nor by the Lungs, may 

 be thrown out upon the surface of the Skin. 



466. What ? 4C7. What arrangement necessary ? Describe Fig. 109. 

 468. How eliminate ? 





