52 Harvey and the [lect. 



" With regard to the lacteal veins discovered by Aselli, and 

 " by the further diligence of Pecquet, who discovered the 

 "receptacle or reservoir of the chyle, and traced the canals 

 " thence to the subclavian veins, I shall tell you freely, since 

 "you ask me what I think of them. I had already in the 

 " course of my dissections, I venture to say even before Aselli 



"had published his book, observed these white canals, But 



"for various reasons, and led by several experiments, I could 

 " never be brought to believe that that milky fluid was chyle 

 "conducted hither from the intestines, and distributed to all 

 " parts of the body for their nourishment ; but that it was 

 " rather met with occasionally and by accident, and proceeded 

 " from too ample a supply of nourishment and a peculiar vigour 

 " of concoction." 



And he goes on to argue against the probability of all the 

 material solid and liquid absorbed from the alimentary canal, 

 taking this path of the lacteals only. " Why indeed should we 

 "not as well believe that the chyle (digested contents of the 

 " intestine) enters the mouth of the mesenteric veins and in 

 " this way becomes immediately mingled with the blood where 



"it might receive digestion and perfection And that the 



" thing is so in fact, I find an argument in the distribution of 

 " innumerable arteries and veins to the intestines, more than to 

 " any other part of the body, in the same way as the uterus 

 " abounds with blood vessels during the period of pregnancy." 



With Harvey's demonstration of the circulation of the blood, 

 supplemented as it was with the discovery of the lymphatics, 

 physiology was almost suddenly transformed. Harvey's work 

 had a double effect. In the first place it rendered possible an 

 exact inquiry into the properties and functions of the organs and 

 tissues of the body. So long as the blood in the arteries and in 

 the veins were looked upon as two different kinds of waves as it 

 were, breaking upon and ebbing from the tissues, the one carry- 

 ing vital, and the other natural spirits, there seemed to be no 

 opening for any attempts to explain the phenomena exhibited 

 by this or that part, this or that organ or tissue on physical or 

 mechanical principles; everything was wrapped up in the 

 mystery of the spirits. So soon however as it was recognized 



