THE NERVOUS SYSTEM 281 



and struggle, for he is in somewhat the same state as the 

 animal without cerebral hemispheres. The use of the sur- 

 geon's knife will still produce movements; respiration may 

 be affected so as to result in groans and other movements 

 which the inexpert observer, perhaps in alarm, attributes to 

 severe suffering ; and yet when the patient awakes he tells 

 us he knew nothing of what passed and felt no pain. It is 

 important to realize that the signs of pain are never reliable 

 evidence of its existence. 



If the anesthesia be pushed further, even these more 

 complicated reflexes disappear. In the ordinary major opera- 

 tions of surgery the ether or the chloroform is given until 

 it interrupts not only the cerebral connections between the 

 afferent and efferent paths but also those of the lower por- 

 tions of the brain; it is even administered until only a few 

 reflexes are left, such as the wink when the cornea is touched, 

 the contraction of the pupil when the eye is exposed to light, 

 etc. these serving as useful tests of the condition of the 

 patient. If, for example, the pupil no longer contracts to 

 light, it is an indication that the anesthesia is going too far 

 too near the point where the nervous mechanism of respi- 

 ration, etc., will be paralyzed. The giving of ether is then 

 suspended until these reflexes are again well established. 



After the operation, as the ether or chloroform is elimi- 

 nated from the system, the reflexes return in the reverse 

 order; and the unconscious movements, groans, incoherent, 

 or even more or less coherent, talking (comparable with 

 talking in one's sleep) are sometimes most harrowing to the 

 feelings of those who do not understand that they are all 

 unconscious acts. The physician and nurse who remain un- 

 moved may even be wrongly charged with lack of feeling 

 because they do not waste sympathy where they know there 

 is neither suffering nor consciousness. 



15. Inhibitory phenomena in the nervous system. We have 

 learned that some nerves excite organs to activity, while 



