MOTION OF THE HEART AND BLOOD 



on the inner lining of these vessels. They are placed 

 differently in different individuals, but are attached 

 to the sides of the veins, and they are directed 

 upwards toward the main venous trunks. As there 

 are usually two together, they face and touch each 

 other, and their edges are so apt to join or close 

 that they prevent anything from passing from the 

 main trunks or larger veins to the smaller branches. 

 They are so arranged that the horns of one set are 

 opposite the hollow part of the preceding set, and 

 so on alternately. 



The discoverer of these valves and his followers 

 did not rightly appreciate their function. It is 

 not to prevent blood from falling by its weight into 

 areas lower down, for there are some in the jugular 

 vein which are directed downwards, and which prevent 

 blood from being carried upwards. They are thus 

 not always looking upwards, but more correctly, 

 always towards the main venous trunks and the 



which gave such glory to Padua where they taught. Harvey studied 

 under Fabricius from 1598 to 1602. Vesalius was a pupil of J. Sylvius 

 (1478-1555) at Paris. 



It is likely that G. Canano (15 15-1578) first described the valves 

 in the veins. C. Estienne (d. 1564) had observed valves in the portal 

 veins (not present in man) in 1538, and J. Sylvius commented on 

 them posthumously. The first published drawings of venous valves 

 were by S. Alberti, De Valvulis, 1585, who acknowledged indebted- 

 ness to Fabricius. The latter demonstrated them publicly in 1579 

 and published his De venarum osteolis in 1603. Harvey employed to 

 make his two plates the same Frankfort craftsman who had made 

 the copper-plates for the 1624 edition of Fabricius (H. Gushing and 

 E. C. Streeter, Monumenta Medica, IF, Canano, Florence, 1925). 

 For a comprehensive historical survey of valves in veins, see Franklin, 

 K. J., Proc. Roy. Soc. Med. (Sect. Hist. Med.) 21: i, 1927. 



I97I 



