454 



EXCRETION. 



drawn from the paralyzed side, in each instance, with great difficulty, and but a small 

 quantity could be obtained. 



The specimens were all examined for cholesterine, with the following results : 



Table of Quantities of Cholesterine in Blood of Paralyzed and Sound Sides, 

 in Three Cases of Hemiplegia. 



The result of these examinations is very interesting: not a single crystal of choleste- 

 rine was found in any of the three specimens of blood from the paralyzed side, while 

 about the normal quantity was found in the blood from the sound side. As the nutrition 

 of other tissues is interfered with in paralysis, it is impossible to say positively, from 

 these observations alone, that cholesterine is produced in the nervous system only. 

 But the nutrition of the nerves is undoubtedly most aifected ; and these observations, 

 taken in connection with the preceding experiments on animals, point very strongly to 

 such a conclusion. 



Our experiments upon animals were so marked and invariable in their results, even 

 when performed under different conditions, that they leave hardly any doubt of the 

 fact that the blood, in passing through the brain, takes up cholesterine. It is more diffi- 

 cult to show, by actual demonstration, that the general system of nerves also gives up 

 cholesterine to the blood ; but the fact that the venous blood coming from the extremi- 

 ties contains more cholesterine than the arterial blood, taken in connection with the 

 fact that none of the tissues of the extremities contain cholesterine, except the nerves, 

 renders it more than probable that the nerves, as well as the brain, are the seat of the 

 formation of this principle. 



Elimination of Cholesterine hy the Liner. We attempted to demonstrate experimen- 

 tally the separation of cholesterine from the blood by the liver, in the same way that we 

 determined its passage into the blood circulating through the brain. In the first series 

 of experiments upon this subject, we endeavored to show, in the same animal, the origin 

 of cholesterine in certain parts, and the mechanism of its elimination. In these experi- 

 ments, which were only approximative, as we had not then succeeded in extracting the 

 cholesterine perfectly pure, we commenced with the arterial blood, examining it as it 

 went to the brain by the carotid, analyzing the substance of the brain, then analyzing 

 the blood as it came from the brain by the internal jugular, examining the blood as it 

 went to the liver by the hepatic artery and portal vein, examining the secretion of the 

 liver, then the blood as it came from the liver by the hepatic vein, examining, also, 

 the blood of the abdominal vena cava. The analyses of the blood from the carotid, inter- 

 nal jugular, and vena cava, have already been referred to in treating of the origin of 



