266 THE LAWS OF ORGANIC 



stated to my friends who kindly assisted me, 

 that it was not improbable we should observe 

 the same results on employing chemical means, 

 in one instance, on a small portion of the brain, 

 if this were in the vicinity of the larger vessels 

 transmitting the blood to the chest, that we ob- 

 serve in another if the portion be much more 

 extensive and confined to the surface. To prove 

 the truth of this opinion, I had a small tube 

 made about three inches long ; the aperture of 

 the superior end was half an inch in diameter ; 

 that of the inferior, applied to the base of the 

 brain, was one-eighth of an inch. When this 

 tube was introduced, the smaller end was made 

 impervious, until it had reached the base, by a 

 slender piece of wood, in order to prevent the 

 brain from filling the tube, which it had previ- 

 ously done in some of my earliest experiments, a 

 circumstance which tended to retard absorption, 

 as the contents of the instrument had lost all con- 

 nexion with the brain, and become as inorganic 

 matter. Adult rabbits were employed in this 

 series of experiments. 



EXPERIMENT I. 



The animal being made insensible by a blow upon the 

 occiput, the chest was opened, that we might observe the 

 contractions of the heart ; and afterwards a small portion 

 of the skull-cap was removed, to allow the introduction of 

 the instrument. A few drops of prussic acid were then 



