THE CIRCULATION 

 I. GENERAL ARRANGEMENT 



THE arrangement by which the blood and lymph are dis- 

 tributed to the tissues may be compared to a great irrigation 

 system. 



It consists of a central force pump the systemic heart (fig. 

 107, S.H.} from which pass a series of conducting tubes the 

 arteries leading off to every part of the body, and ending in 



UUNC 



CAP 



FIG. 107. Scheme of the Circulation. S.H., systemic heart sending blood to 

 the capillaries in the tissues, Cap. The blood brought back by veins and 

 the exuded lymph by lymphatics, Ly., passing through glands; blood 

 sent to the alimentary canal, Al.C., and from that to the liver, Liv. ; 

 blood also sent to the kidneys, Kid. ; the blood before again being sent 

 to the body is passed through the lungs by the pulmouic heart, P.H. 



innumerable fine irrigation channels the capillaries (Cap.} 

 in the substance of the tissues. From these, a considerable 

 proportion of the blood constituents is passed into the spaces 

 between the cells as lymph. From these spaces the fluid is 

 either passed back into the capillaries, or is conducted away in 

 a series of lymph vessels, which carry it through lymph glands 



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