AN ANATOMICAL STUDY ON THE 



heart. Others as well as myself have sometimes 

 found them in the milky veins^ and in the venous 

 branches of the mesentery directed towards the 

 vena cava and portal vein. To this may be added 

 that there are none in the arteries, and that one 

 may note that dogs, oxen, and all such animals 

 have valves at the branches of the crural veins 

 at the top of the sacrum, and in branches from the 

 haunches, in which no such weight effect of an erect 

 stature is to be feared. 



Nor, as some say, are the valves in the jugular 

 veins to prevent apoplexy, since the head is more 

 likely to be influenced by what flows into it through 

 the carotid arteries.^ Nor are they present to keep 

 blood in the smaller branches, not permitting it to 

 flow entirely into the larger more open trunks, 



2 Does Harvey mean the lacteals? The Galenical error, to which 

 Harvey subscribed, that the veins of the mesentery carried chyle to 

 the liver, was cleared up by G. Aselli (1581-1626) who discovered 

 the lacteals {De lactibus, Milan, 1627), by J. Pecquet (1622-1674) 

 who showed their passage to the thoracic duct and then to the sub- 

 clavian vein {Experimenta nova, Paris, 165 1), and by O. Rudbeck 

 (1639-1702) and T. Bartholin (1616-1680) who discovered the in- 

 testinal lymphatics and their connection with the thoracic duct. 

 Pecquet's work contained a carefully devised proof of Harvey's 

 doctrine. On April 28, 1652, Harvey wrote a letter to Dr. R. Morison 

 of Paris (see Willis's translation of Harvey's works, Sydenham 

 Society, 1847, P- ^"^4) '" which he discussed Pecquet's contribution. 

 His characteristic conservatism prevented him from accepting the 

 discovery, although it offered a demonstrable explanation of an un- 

 satisfactory portion of his own. 



^ An idea partially expressed in their very name, "the arteries 

 of sleep." This name may have developed from the early observation 

 (used for anesthetic purposes by the Assyrians) that pressure on these 

 vessels might be followed by fainting. 



[98I 



