13 



five days, after which the opacity disappeared and no trace re- 

 mained of it, or of the ridge. This experiment has been made 

 on guinea-pigs. 



2. I have found a considerable hypertrophy of the two supra- 

 renal capsules, on eight or ten guinea-pigs, upon which a lateral 

 half of the spinal cord had been cut in the dorsal region, for 

 eight, ten or fifteen months. These organs had acquired, in 

 some of these cases, three times their natural dimensions, and in 

 others only the double. There was no appearance of change in 

 their structure. 



By an examination of the supra-renal capsules in guinea-pigs, 

 on which I had made the section of a lateral half of the spinal 

 cord, a few hours or a few days previously, I have found these 

 organs congested, and sometimes containing even a slight effu- 

 sion of blood. It is very probable that such a congestion has 

 been the cause of the hypertrophy found in animals operated on 

 at a much longer time previously. The congestion is certainly 

 the result of a peculiar disturbance in the nervous action. A 

 part only of the spinal cord appears to possess that singular 

 influence on the supra-renal capsules. That part is extended, 

 in guinea-pigs, from the tenth costal vertebra to the third lumbar. 



A simple puncture of the cord is frequently sufficient to pro- 

 duce the congestion of both supra-renal capsules. 



3. The researches, made before mine, as to the influence of 

 the spinal cord on the urinary secretion, could not give a decided 

 result, because no physiologist had been able to keep any warm- 

 blooded animal living a sufficient time, after the destruction of a 

 large part of the spinal cord. 



The results obtained by S^galas on seme animals who have 

 lived from fifteen minutes to an hour after the destruction of the 

 lumbar part of the cord, had led him to conclude that the spinal 

 cord has no influence on the urinary secretion. Longet (Trait 

 de Physiologic, Paris, 1850, t. ii. B. p. 199) says : " Many ob- 

 servations have demonstrated to me that the visceral organs, 

 which receive their nerves from the sympathetic, are far from 

 being immediately paralyzed by the section of these nerves, and 

 that their action is even maintained much longer than the dura- 

 tion of the experiments in which Segalas had destroyed the spinal 



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