Circulation of the Blood 157 



become more consistent or earthy, so penetrative as 

 when it is more serous and attenuated or liquid. And 

 then it seems only reasonable to think that the blood 

 in its circuit passes more slowly through the kidneys 

 than through the substance of the heart ; more swiftly 

 through the liver than through the kidneys ; through 

 the spleen more quickly than through the lungs, and 

 through the lungs more speedily than through any of 

 the other viscera or the muscles, in proportion always 

 to the denseness or sponginess of the tissue of each. 



We may be permitted to take the same view of the 

 influence of age, sex, temperament, and habit of body, 

 whether this be hard or soft ; of that of the ambient 

 cold which condenses bodies, and makes the veins 

 in the extremities to shrink and almost to disappear, 

 and deprives the surface both of colour aud heat ; 

 and also that of meat and drink which render the 

 blood more watery, by supplying fresh nutritive matter. 

 From the veins, therefore, the blood flows more freely 

 in phlebotomy when the body is warm than when it is 

 cold. We also observe the signal influence of the 

 affections of the mind when a timid person is bled and 

 happens to faint : immediately the flow of blood is 

 arrested, a deadly pallor overspreads the surface, the 

 limbs stiffen, the ears sing, the eyes are dazzled or 

 blinded, and, as it were, convulsed. But here I come 

 upon a field where I might roam freely and give myself 

 up to speculation. And, indeed, such a flood of light 

 and truth breaks in upon me here ; occasion offers of 

 explaining so many problems, of resolving so many 

 doubts, of discovering the causes of so many slighter 

 and more serious diseases, and of suggesting remedies 

 for their cure, that the subject seems almost to demand 

 a separate treatise. And it will be my business in my 

 ' Medical Observations," to lay before my reader matter 

 upon all these topics which shall be worthy of the 

 gravest consideration. 



And what indeed is more deserving of attention than 



