NATURAL HISTORY. 39 



With milVy blood the heai't is overflown, 



Is soothed and sweetened by the social sense." THOMSO*. 



and lung's could be touched through the opening without imparting any feeling 

 that they were touched. Harvey says : " When I paid my respects to this young 1 

 nobleman, he made no concealment, but exposed the left side of his breast, when I 

 saw a cavity into which I could introduce my fingers and thumb. Astonished with 

 the novelty, I again and again explored the wound, and first marvelling at the 

 extraordinary nature of the cure, I set about the examination of the heart. Taking 

 it in one hand and placing the finger of the other on the pulse of the wrist, I satis- 

 fied myself that it was indeed the heart which I grasped. I then brought him to 

 the King (Charles I.), that he might behold and touch so extraordinary a thing, and 

 that he might perceive, as I did, that unless when we touched the outer skin, or 

 when he saw our fingers in the cavity, this young nobleman knew not that we 

 touched the heart." 



110. Why do the, interior organs of the, body keep in the placet 

 assigned them, when the body itself is moved about in every 

 direction. 



Because the various parts are tied or fastened to the body in 

 such a manner as to prevent them slipping from their places. 



111. The heart is placed between two soft lobes of the lungs, and is tied to the me- 

 diastinum and to the pericardium, which pericardium is not only itself a very strong 

 membrane, but adheres firmly to the duplicature of the mediastinum, and, by its 

 point, to the middle tendon of the diaphragm. The heart is also sustained in its 

 place by the great blood-vessels which issue from it. The lungs are tied to the 

 sternum by the mediastinum before, to th*> vertebrae by :he pleura behind. It seems 

 indeed to be the very use of the mediastinum (which is a membrane that goes 

 straight through the middle of the thorax, from the breast to the back) to keep th<" 

 contents of the thorax in their places ; in particular to hinder one lobe of the lungs 

 from incommoding another, or the parts of the lungs from pressing upon each other 

 when we lie on the side. The liver is fastened in the body by two ligaments ; the 

 first, which is large and strong, comes from the covering of the diaphnisnn. and 

 penetrates the substance of the liver ; the second is the umbilical vein, whicn, alter 

 birth, degenerates into a lig-ament. The first, which is the principal, fixes the liver 

 in its situation whilst the body holds an erect posture ; the second prevents it from 

 pressing on the diaphragm when we he down ; and both together sling or suspend 

 the liver when we lie upon our backs, so thnt it may not compress or obstruct the 

 vein to which belongs the important office of returning the blood from the body to 

 the heart. 



