400 THE NERVOUS SYSTEM. 



spinal cord, and thence reflected to the motor nerves supplying 

 the Fallopian tubes. The involuntary action of the uterus in 

 expelling its contents during parturition, is also of a purely 

 reflex kind, dependent in part upon the spinal cord, though 

 in part also upon the sympathetic system : its independence of 

 the brain being proved by cases of delivery in paraplegic 

 women, and now more abundantly shown in the use of chloro- 

 form. 



Besides these acts regularly performed under the influence 

 of the reflecting power of the spinal cord, others are manifested 

 in accidents, such as the movement of the limbs and other 

 parts to guard the body against the effects of sudden danger. 

 When, for example, a limb is pricked or struck, it is instantly 

 and involuntarily withdrawn from the instrument of injury ; 

 and the same preservative tendency of the reflex power of the 

 cord is shown in the outstretched arms when falling forwards, 

 and their reversed position when falling backwards ; the 

 action, although apparently voluntary, being really, in most 

 cases, only an instance of reflex action. 



To these instances of spinal reflex action, some add yet 

 many more, including nearly all the acts which seem to be 

 performed unconsciously, such as those of walking, running, 

 writing, and the like : for these are really involuntary acts. 

 It is true that at their first performances they are voluntary, 

 that they require education for their perfection, and are at all 

 times so constantly performed in obedience to a mandate of 

 the will, that it is difficult to believe in their essentially in- 

 voluntary nature. But the will really has only a controlling 

 power over their performance ; it can hasten or stay them, but 

 it has little or nothing to do with the actual carrying out of 

 the effect. And this is proved by the circumstance that these 

 acts can be performed with complete mental abstraction : and, 

 more than this, that the endeavor to carry them out entirely 

 by the exercise of the will is not only not beneficial, but posi- 

 tively interferes with their harmonious aud perfect perform- 

 ance. Any one may convince himself of this fact by trying 

 to take each step as a voluntary act in walking down stairs, 

 or to form each letter or word in writing by a distinct exercise 

 of the will. 



These actions, however, will be again referred to, when 

 treating of their possible connection with the functions of the 

 so-called sensory ganglia (p. 413). 



The phenomena of spinal reflex actions in man are much 

 more striking and unmixed in cases of disease. In some of 

 these, the effect of a morbid irritation, or a morbid irritability 

 of the cord, is very simple ; as when the local irritation of 



