REFLEX ACTION OF THE SPINAL CORD. 415 



patient. The discharges are then said to be " involuntary and un- 

 conscious." 



If the irritability of the cord, on the other hand, be exaggerated 

 by disease, while its connection with the brain remains entire, the 

 distension of the rectum is announced by the usual sensation, but 

 the reflex impulse to evacuation is so urgent that it cannot be 

 controlled by the will, and the patient is compelled to allow it to 

 take place at once. The discharges are then said to be simply 

 " involuntary." 



Finally, if the substance of the spinal cord be extensively de- 

 stroyed by accident or disease, the sphincter is permanently relaxed. 

 The feces are then evacuated almost continuously, without any 

 knowledge or control on the part of the patient, as fast as they 

 descend into the rectum from the upper portions of the intestine. 



Injury of the spinal cord produces a somewhat different effect on 

 the urinary bladder. Its muscular fibres are directly paralyzed ; 

 and the organ, being partially protected by elastic fibres, both at 

 its own orifice and along the urethra, becomes gradually distended 

 by urine from the kidneys. The urine then overcomes the elas- 

 ticity of the protecting fibres, by simple force of accumulation, and 

 afterward dribbles away as fast as it is excreted by the kidneys. 

 Paralysis of the bladder, therefore, first causes a permanent disten- 

 sion of the organ, which is afterward followed by a continuous, 

 passive, and incomplete discharge of its contents. 



Injury of the spinal cord produces also an important, though 

 probably an indirect effect on nutrition, secretion, animal heat, &c., 

 in the paralyzed parts. Diseases of the cord which result in its 

 softening or disintegration, are notoriously accompanied by consti- 

 pation, often of an extremely obstinate character. In complete 

 paraplegia, also, the lower extremities become emaciated. The 

 texture and consistency of the muscles are altered, and the animal 

 temperature is considerably reduced. All such disturbances of 

 nutrition, however, which almost invariably follow upon local para- 

 lysis, are no doubt immediately owing to the inactive condition of 

 the muscles ; a condition which naturally induces debility of the 

 circulation, and consequently of all those functions which are de- 

 pendent upon it. 



It is less easy to explain the connection between injury of the 

 spinal cord and ij>%mmatirm pf t.fre urinary passages. It is, how- 

 ever, a matter of common observation among pathologists, that 

 injury or disease of the cord, particularly in the dorsal and u 



