i is 



through the I ic walla into th< 



thai it i>i- tie apes of t 1 



I fulcra ;tt ti t wall, 



and it' the movements of their 01 I by ti 



hi* the heart, are observed, the) will 1»- fi>un<l to 

 made on I posed heart. 



Mm e particular im esl ignl ii 

 uf the hearl ca> it \ during »le and dij 



making measurements ctions across tl 



these conditions P01 such put I in dii ly "1» 



tained, bul for the heart in Bystole i T 

 artificial means of injecting the heart with ln»t chrom 

 just before the death ••!' the animal. Tl 1 chron 

 muscle tu contracl and maintains it in tl ndition. 1 



tin's.' investigations is. however, not <>t* much practical im] 



Although it is im.v, common knowledge thai the direction of tl . 

 uf the liliiinl is from the veins to the arteri< it may b< 



consider for a momenl th< pal principle of the m< I 



William Harvey sue ided in making tliis discovery. Ii 



partly anatomic, parti; rimental. He pointed oul thai tin 



the veins, and of the auricles to which they lead, are very thin, \. 

 thus.' of the arteries and ventric ry thick, and he 



in the veins the blood musl flow gently from the I 



rt, tu which the valves in tl • ad thai in tl 



it must be propelled by pulses with each systole through 



ards the tissues by tin- contraction of the walls 

 experimental Bupport for this hypothesis he furnished parti) 

 j, veins and arteries leading r from ti 



erving the resulting distension or collapse of 1 1 

 calculation of the amount od which must be expel 

 venl gh en period of t in 



Harv< '- d 

 in»t much added to until exp 1 metl 



the 



and compared. Until Buch a 

 ■ible ti> h ite the mechanism by which t! • 



the heart eai iti< ted v» ith I 



function, or to descrilx • 

 in : 3 during the variot 



It is for the pin 

 cha that int diac p 



