L'DJ Till. NERVOUS SYSTKM AM) ITS COXSKKVATH >\ 



If a layman \>\ cult Tat all upon a theme which properly 

 belongs to the practitioner, he should cite the authority 

 from which he draws most freely. The chief source of the 

 following account is( 'ourtney's "The ( 'onquest of Xerves." ' 

 The hook can be coinnirndcd to all who seek an analysis 

 of neurasthenia at once scientific and sympathetic, with 

 many sane surest ions for its relief. The same author has 

 contributed the section on the nervous system in Pyle's 

 "Personal Hygiene," ' where a more condensed presenta- 

 tion of similar material may be found. 



The nervous system seems to suffer from fatigue of two 

 orders. First, there is that which may be called the daily 

 type, from which complete recovery occurs in the course 

 of a night's sleep. This has been sufficiently discussed (see 

 ('hapter XII). Another type of fatigue is that which is 

 cumulative from day to day, and which cannot be quickly 

 compensated. It results from the coexistence of some 

 or all the factors mentioned in the last chapter, and when 

 it is far enough developed it is recogni/ed as neurasthenia. 

 There is a single principle which proves to be the key to 

 the problem: it is the fact that in nervous fatigue of the 

 central order there is a large element of hypersensitiveness 

 and consequent excessive activity. 



We usually think of fatigue as a distinct depression of 

 capacity for action. This is true in a general way of the 

 neuromuscular system, though even with the simplified 

 conditions of laboratory trials it has been shown that a 

 moderate amount of contraction increases the working 

 power of muscle. Lee has interpreted this as meaning 

 thai the metabolic products of the contractile process. 

 I lie same compounds which in larger quantities will limit 

 the performance of the mechanism, act at first as stimu- 

 lants. This seems to be much more distinctly the case 

 with the neurons of the brain and cord. 



We can often observe in people tired by a day of excite- 

 ment perhaps of sightseeing that there is an appear- 



1 Maunillaii, New York. I'.lll. 



2 \V. B. SauiuliT^ < 'u., I'liilailrlpliia. 



