144 WILLIAM HARVEY 



point or pulsating vesicle, a portion apparently of the umbil- 

 ical vein, dilated at its commencement or base. Afterwards, 

 when the outline of the foetus is distinctly indicated and it 

 begins to have greater bodily consistence, the vesicle in ques- 

 tion becomes more fleshy and stronger, changes its position, 

 and passes into the auricles, above which the body of the 

 heart begins to sprout, though as yet it apparently per- 

 forms no office. When the foetus is farther advanced, when 

 the bones can be distinguished from the fleshy parts and 

 movements take place, then it also has a heart which pul- 

 sates, and, as I have said, throws blood by either ventricle 

 from the vena cava into the arteries. 



Thus nature, ever perfect and divine, doing nothing in 

 vain, has neither given a heart where it was not required, 

 nor produced it before its office had become necessary ; but 

 by the same stages in the development of every animal, pass- 

 ing through the forms of all, as I may say (ovum, worm, 

 foetus), it acquires perfection in each. These points will 

 be found elsewhere confirmed by numerous observations 

 on the formation of the foetus. 



Finally, it is not without good grounds that Hippocra- 

 tes in his book, " De Corde," entitles it a muscle ; its 

 action is the same; so is its functions, viz., to contract 

 and move something else in this case the charge of the 

 blood. 



Farther, we can infer the action and use of the heart 

 from the arrangement of its fibres and its general structures, 

 as in muscles generally. All anatomists admit with Galen 

 that the body of the heart is made up of various courses of 

 fibres running straight, obliquely, and transversely, with ref- 

 ference to one another; but in a heart which has been 

 boiled, the arrangement of the fibres is seen to be different 

 All the fibres in the parietes and septum are circular, as in 

 the sphincters; those, again, which are in the columns ex- 

 tend lengthwise, and are oblique longitudinally ; and so it 

 comes to pass that when all the fibres contract simultaneously, 

 the apex of the cone is pulled towards its base by the col- 

 umns, the walls are drawn circularly together into a globe 

 the whole heart, in short, is contracted and the ventricles 

 narrowed. It is, therefore, impossible not to perceive that, 





