Chapter I 



The Author* s Reasons for tf^riting 



"•>— — ^>-«-<^"— •<••■ 



WHEN I first tried animal experimentation for 

 the purpose of discovering the motions and 

 functions of the heart by actual inspection and not 

 by other people's books, I found it so truly difficult 

 that I almost believed with Fracastorius,^ that the 

 motion of the heart was to be understood by God 

 alone. I could not really tell when systole or diastole 

 took place, or when and where dilatation or constric- 

 tion occurred, because of the quickness of the move- 

 ment. In many animals this takes place in the 

 twinkling of an eye,'like a flash of lightning. Systole 

 seemed at one time here, diastole there, then all 

 reversed, varied and confused. So I could reach no 

 decision, neither about what I might conclude myself 

 nor believe from others. I did not marvel that 

 Andreas Laurentius wrote that the motion of the 

 heart was as perplexing as the flux and reflux of 

 Euripus* was to Aristotle. 



* De sympathia et antipathia, Cap. 75, Opera Omnia, Venice, 1555 

 p. 95. H. Fracastorius (1484-1553) was the author of the famous 

 poem which gave the name to the disease syphilis, Lii>. Tres Syphilidis, 

 she Morbi Gallici (1530). 



2 A narrow channel 113 miles long, between Euboea and Boeotia, 

 opposite Chalcis, renowned in antiquity for the violent flow and reflow 

 of its tide. 



[25] 



