V SPINAL CORD AND NERVES 355 



vessels of the hind-limbs in the same way as those of the fore- 

 limbs. 



Owing to this local excitability of the cutaneous vessels, the 

 cordless animal is capable of maintaining its normal blood 

 temperature during marked oscillations of the external tempera- 

 ture, and though it is necessary to keep it in a chamber with 

 constant temperature immediately after the operation, this pre- 

 caution becomes unnecessary in a few weeks. 



At the season for changing the coat, a marked difference is 

 seen in the hair of the anterior and posterior parts of the body ; 

 in the former it is new and glossy, in the latter it is dull and 

 lifeless, and comes out at the least pull. 



From these phenomena as a whole we must conclude that 

 the cord is not absolutely indispensable to life in warm-blooded 

 vertebrates, but that it is important to the visceral functions. 



The absence of the spinal centres is responsible for the low 

 energy with which these functions are carried out under the 

 exclusive influence of the sympathetic system, and the great 

 instability in the health and vitality of the cordless animal, which 

 requires constant care, and easily falls ill and succumbs to 

 slight causes. 



The closure of the anal sphincter in a dog in which the cord 

 is simply transected is firmer than after removal of the cord, and 

 the rhythmic reflex contractions of the anus that are easily seen 

 in the " spinal " animal are exceedingly rare in the " sympathetic " 

 animal. 



Even more striking is the diminished energy of the vesical 

 functions in the cordless animal ; the bladder, moreover, is often 

 infected, and most of the animals die of cystitis and pyelo- 

 nephritis. Only in rare cases has it been possible to cure the 

 cystitis when it has once set in. 



Digestive disorders, again, are very dangerous to the animal 

 that has lost its cord. 



Finally, in the cordless animal thermal regulation is only 

 possible with limited variations of the external temperature. 



These important observations of Goltz and Ewald on the 

 symptoms produced by removal of the spinal cord enable us to 

 appraise the value of the early doctrine (see p. 278), by which the 

 sympathetic system was held to preside over the functions of 

 visceral life. Undoubtedly all such activities may subsist and 

 function in a comparatively normal fashion after removal of all 

 spinal influence. The office of the spinal system in regard to the 

 functions of visceral life seems to consist in endowing these 

 functions with greater energy, and in conferring greater stability 

 and more solid equilibrium on the general constitution of the 

 animal. 



