CIRCULATION OF THE BLOOD. 95 



and penetrating than the chyle or milk contained in these 

 lacteal vessels, and is further impelled by the pulsations of the 

 arteries that it may find a passage by other channels. 



Our learned author mentions a certain tract of his on the 

 Circulation of the Blood : I wish I could obtain a sight of it ; 

 perhaps I might retract. But had the learned writer been so 

 disposed, I do not see but that having admitted the circular 

 motion of the blood, 1 all the difficulties which were formerly felt 

 in connexion with the distribution of the chyle and the blood 

 by the same channels are brought to an equally satisfactory 

 solution ; so much so indeed that there would be no necessity 

 for inquiring after or laying down any separate vessels for the 

 chyle. Even as the umbilical veins absorb the nutritive juices 

 from the fluids of the egg and transport them for the nutrition 

 and growth of the chick, in its embryo state, so do the meseraic 

 veins suck up the chyle from the intestines and transfer it to 

 the liver; and why should we not maintain that they perform 

 the same office in the adult ? For all the mooted difficulties 

 vanish when we cease to suppose two contrary motions in the 

 same vessels, and admit but one and the same continuous mo- 

 tion in the mesenteric vessels from the intestines to the liver. 



I shall elsewhere state my views of the lacteal veins when I 

 treat of the milk found in different parts of new-born animals, 

 especially of the human subject ; for it is met with in the me- 

 sentery and all its glands, in the thymus, in the axillae, also in 

 the breasts of infants. This milk the midwifes are in the habit 

 of pressing out, for the health, as they believe, of the infants. 

 But it has pleased the learned Riolanus, not only to take away 

 circulation from the blood contained in the mesentery; he affirms 

 that neither do the vessels in continuation of the vena cava, 

 nor the arteries, nor any of the parts of the second and third 

 regions, admit of circulation, so that he entitles and enumerates 

 as circulating vessels the vena cava and aorta only. For this 

 he appears to me to give a very indifferent reason^ "The 

 blood," he says, " effused into all the parts of the second and 

 third regions, remains there for their nutrition; nor does it 



1 Enchiridion, lib. iii, cap. 8 : " The blood incessantly and naturally ascends or 

 flows back to the heart in the veins, as in the arteries it descends or departs from the 

 heart." 



a Enchirid. lib. iii, cap. 8. 



