| Show tim TIIE hearts MECHANISM the tiie human heart isa I 1 wonderful piece plede of mechanism a is a clumsy contrivance comp compares compared ired with it man mau iles lies lla ile two hearts lie arts and each rach or of thee ia is double eo so that lie may be said to have four hearts two of th thae se are for bright red blood and rind two are for purple or dark blood it is usual in books to call red blood arterial arte rui rul and und the purple blood venous but each bac I 1 I 1 of these two double hearts has lias its own set of arteries and avid veins and the arteries of tho the one are always filled with red and the art arteries cries of the tilo other oilier with purple blood the velus veins in like manner of each are iu in invers inverse order the veins of the red heart being purple and the relus velus of or the purple being red for if the blood goes out red it comes back buck purple and if ir it goes out au t purple it comes back red it always goes out red from the tha heart hart ou on the tile left side bide and comes iu in purple to the heart on the right side and it always goes 0 out u t purple from the heart on the right side and ud c comes om s in red to the heart oil on the leit left side a and thur thus thurit it makes its everlasting round bein con vel vei veiled ted led from 11 purple to red by passing pissing gli gir 41 the tho lungs each heart henrt has bas its s going and returning 9 arlex arles rles rica of or vessels ii finitely numerous und and and rati rail ift rd fied and the blood is forced through gli them in hi such a way that it must go forward and und cannot return except by going round the circle circie cir clr cli cil for these vessels are all bup dup applied plied with valves that open only one ona way and shut the tile other and therefore were tha blood to ranke an till effort to cretu ru tha valves would cloe immediately and stop slop it the elastic eli elf nature of uis his blood vessels also la Is such that they thoy squeeze the blood in undulations u or pulsations along t losing closing upon it an I 1 then open ing to let more forward and all this thid they do epou spon and regularly the tiie will of man titan havin having P nothing to do with it nud oud no power oyer over tilt tile their movement ex |
