600 



From these facts, and a great many others, it results that in the 

 spinal cord, the sensitive and motor nerves, and the sympathetic, as 

 well as in muscles, there is an increase of the vital properties produced 

 by oxygen. 



VI. " Summary of a paper (to be presented) on the Power 

 possessed by Motor and Sensitive Nerves of retaining their 

 Vital Properties longer than Muscles, when deprived of 

 Blood." By E. BROWN-SEQUARD, M.D. Communicated 

 by JAMES PAGET, Esq., F.B.S. Received July 3, 1857. 



It is an admitted doctrine that the vital properties of motor and 

 sensitive nerves disappear much sooner than those of muscles, after 

 death, or when they are deprived of blood. Although founded on 

 positive facts, this theory is not correct, these facts being capable of 

 another interpretation. In the experiments made heretofore, other 

 organs (such as the spinal cord and muscles) had been deprived of 

 blood, at the same time with the sensitive and motor nerves. To 

 ascertain the influence of the deprivation of blood on nerves alone, it 

 was necessary to experiment otherwise than has been done hitherto. 

 I will in this short summary show, only by a few experiments taken 

 at random among many, that the essential vital properties of sensi- 

 tive and motor nerves can last longer than muscular irritability after 

 a complete or almost complete deprivation of blood. 



Exp. 1. After having placed ligatures around the arteries of the 

 upper part of the thigh of a young Guinea-pig, I amputated the 

 limb, leaving the sciatic and crural nerves uninjured. In the whole 

 length of the thigh I then laid bare these nerves, and dissected their 

 neurilemma all along, so as to cut away as much as possible the 

 little supply of blood they received from above. Voluntary move- 

 ments existed about 8 minutes in the amputated leg ; excitation of 

 the trunks of the exposed nerves continued to produce muscular con- 

 tractions for 6 minutes more. 



In the whole length of the amputated limb, 10 minutes after the 

 operation, sensibility was greater than in the other limbs. Mus- 

 cular irritability disappeared in the amputated leg from 30 to 40 



