154 PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



eral results obtained by Goltz * in some remarkable experiments 

 in which the entire cord was removed with the exception of the 

 cervical region and a small portion of the upper thoracic. In 

 making this experiment it was necessary to perform the operation 

 in several steps. That is, the cord was first sectioned in the upper 

 thoracic region and then in successive operations the lower tho- 

 racic, lumbar, and sacral regions were removed completely. Very 

 great care was necessary in the treatment of the animals after 

 these operations, but some survived and lived for long periods, 

 the digestive, circulatory, and excretory organs performing their 

 functions in a normal manner. The muscles of the hind limbs 

 and trunk, however, underwent complete atrophy, owing to the 

 destruction of their motor nerves. The blood-vessels also were 

 paralyzed after the first operations, but gradually their muscu- 

 lature again recovered tone, showing that, although under normal 

 conditions the tonic contraction of the vessels is under the in- 

 fluence of nerves arising from the cord, this tone may be re-estab- 

 lished in time after the severance of all spinal connections. Some 

 of the specific results of these experiments, bearing upon the re- 

 flexes of defecation, micturition, and parturition, will be described 

 later. Attention may be called here to the general results 

 illustrating the general functions of the cord. 



In the first place, there was, of course, a total paralysis of volun- 

 tary movement in the muscles innervated normally through the 

 parts of the cord removed, and a complete loss of sensation in the 

 same regions, particularly of cutaneous and muscular sensibility. 

 In the second place, the visceral organs, including the blood-vessels, 

 were shown to be much more independent of the direct control of 

 the central nervous system. While these organs in the experiments 

 under consideration were still in connection with the sympathetic 

 ganglia and in part with the brain through the vagi, still their 

 connections with the central nervous system, particularly as 

 regards their sensory paths and the innervation of the blood-vessels, 

 were in largest part destroyed. The immediate effect of this 

 destruction would have been the death of the animal if the care 

 of the observer had not replaced, in the beginning, the normal 

 control exercised by the nervous system through the spinal nerves; 

 but later this careful nursing was not required. While these organs, 

 therefore, are capable of a certain amount of independent activity 

 and co-ordination, they are normally controlled through the various 

 reflex activities of the brain and cord. In the third place, it is 

 noteworthy that the adaptability of the cordless portion of the 

 animal was distinctly less than normal. Its power of preserving a 



* Goltz and Ewald, "Pfliiger's Archiv fur die gesammte Physiologie," 63, 

 362, 1896. 



