THE CIRCULATION IOQ 



enter the blood. The lymphatics penetrate and help in 

 the nourishment of every tissue, even in that of the bony 

 tissue (Fig. 102). 



185. The Spleen. This organ resembles the lymph nodes. 

 It is purplish red, about five inches in length, and is situ- 

 ated just inside of the lower 



ribs on the left side of the 

 abdomen. White corpuscles 

 are formed in it as well as in 

 the smaller lymph nodes. In 

 it also the red corpuscles that 

 have finished their service 

 in the blood are probably 

 broken up and destroyed. 



HYGIENE OF THE CIRCU- FIG. 102. Section of a Haversian 

 T ATTrkxr Canal, showing its Contents, highly 



magnified. 



186. Have VOU learned Vet a > sma11 arterial capillary vessel; v, large 



J venous capillary; , pale nerve fibers cut 



the CUrioUS fact that all 01 the across ; /, cleftlike lymphatic vessel; one 



,.. ,, r , j i f the cells forming its wall communi- 



llVing CellS 01 the DOdy live cates by fine branches with the branches 



under water, j ust as the ameba of a bone corpuscle - 

 does ? The lymph and the blood are chiefly water and the 

 cells are all bathed continually in one or the other. The 

 blood bathes the cells in the walls of its vessels, and the 

 lymph, or the blood without the red corpuscles, is found 

 filling the interstices or spaces between the cells, like water 

 in a sponge. From the spaces, as we learned, it is taken 

 by the lymphatics in order to make room for fresh lymph, 

 free from waste material and bringing fresh nourishment. 

 The only exception to the rule that the cells live a 

 watery existence, is found on the surface of the body ; the 

 cells of the outer skin, hair, and nails, however, may be 

 called dying cells, for they are not alive in the same sense 

 that the other cells are : they do not contain nuclei and 

 cannot repair themselves or grow. 



