MODIFICATIONS OF THE SECRETION OF UKEN'E. 173 



by a little more than fifty per cent. In another animal, he 

 diminished the pressure by taking blood from the jugular 

 vein, and the quantity of urine was immediately reduced 

 about one-half. 1 His later observations on this subject 

 showed that the increase in the quantity of urine produced 

 by exaggerated pressure of blood in the kidneys was capable 

 of being modified through the nervous system. In these ex- 

 periments, the nerves going to one kidney were divided, 

 which produced an increase in the arterial pressure and a 

 consequent exaggeration in the quantity of urine from the 

 ureter on that side. The pressure was then further increased 

 by stopping the nostrils of the animal. The quantity of 

 urine was increased by this on the side on which the nerves 

 had been divided, but the pain and distress from want of air 

 arrested the secretion upon the sound side. 2 



The precise influence which special nerves exert upon the 

 secretion of urine has not yet been positively ascertained. 

 Some important facts, however, bearing upon this subject 

 have been developed of late years. In his interesting and 

 novel experiments upon artificial diabetes in animals, Ber- 

 nard found that when irritation was applied to the floor of 

 the fourth ventricle, in the median line, exactly in the mid- 

 dle of the space comprised between the origin of the pneu- 

 mogastrics and the auditory nerves, the urine was increased 

 in quantity and became strongly saccharine. When the irri- 

 tation was applied a little above this point, the urine was sim- 

 ply increased in quantity, but contained no sugar ; and when 

 the puncture was made a little below, sugar appeared in the 

 urine, without any increase in the quantity of the secretion. 3 

 It has also been observed that section of the spinal cord in 

 the upper part of the dorsal region arrests, for a time, the 

 secretion of urine. 4 



1 BERNARD, Liquidts de Forganisme, Paris, 1859, tome ii., p. 155. 

 - Unpublished lectures delivered at the College of France in the Summer 

 of 1861. 



3 BERNARD, Lemons de physiologic experimentale, Paris, 1855, p. 339. 



4 BERNARD, Unpublished lectures, 1861. 



