488 REPORTS ON THE STATE OF SCIENCE. 



possibility of general fatigue of this nature is, I think, especially important 

 from the point of view of the physician. 



The long continuance of the chronic fatigues with which the physician 

 so often has to deal seems to show that, in many cases at least, these are 

 not toxic fatigues (the only kind of general fatigue admissible under the 

 too simple Verworn scheme). They seem to imply the exhaustion of some 

 of the sources of energy, which rendering the maintenance of a due 

 general pressure or potential of free energy impossible, keeps the ratio of 

 resistance to energy high in all parts of the nervous system. 



I have already kept you too long, but I should like, greatly daring, to 

 suggest how the conception of fatigue as an increased ratio of resistance 

 to enei'gy may possibly help us in arriving at an understanding of some 

 nervous disorders. 



A due balance between resistances and energies is essential to health, 

 and it seems possible a priori that the balance may be disturbed by 

 disorder primarily affecting either factor. 



Suppose that, as an innate constitutional peculiarity, the resistances 

 are deficient relatively to the energies in an otherwise normal or well- 

 endowed brain ; we should expect to see the possessor of such a brain 

 an excitable sensitive person who, the great protective system being 

 deficient, easily works himself to the point of exhaustion ; exhaustion 

 rather than fatigue will be his peculiarity. He is readily provoked to a 

 great and rapid output of energy, and his brain does not easily return to 

 rest ; general excitement is slow to die away, and he finds difficulty in 

 sleeping after any effort, for the condition of increased and predominant 

 resistance is not easily attained ; the system remains uselessly at work and 

 wears itself out ; thei'e follows exhaustion secondarily developed, owing 

 to the deficiency of the protective system of resistances. We should then 

 get the typical picture of the hereditary or born neurasthenic ; the dis- 

 order is brought on by any strenuous coui'se of life, and its early stages 

 are characterised by hyperesthesias of all sorts, undue .sensitiveness 

 to all sense-impressions, general irritability or irritable weakness, in- 

 somnia, increased reflexes ; the patient may have the power of working 

 sometimes extremely effectively for a short time, but such work soon 

 leads to exhaustion and leaves the patient incapable for a long time of 

 again getting up a sufficient head of nervous pressure to renew his 

 labours. It is, I think, in harmony with this view that some of our most 

 brilliant and original intellects have shown marked neurasthenic tendency 

 e.f/., Charles Darwin and Herbert Spencer. 



The neurasthenia induced by shocks — e.g., the mental and physical 

 shocks of a railway accident — may possibly be brought into line by the 

 supposition that the brief and general overstimulation of the nervous 

 .system, which was too sudden to allow the increase of resistances to play 

 their normal protective part, has more or less paralysed the synaptic 

 process, so that they no longer are capable of building up and maintaining 

 the due resistances, and again ii-ritable weakness dominates the scene. 



In this way it seems to me we may perhaps account for the para- 

 doxical character of neurasthenia, for its combination of excess and 

 defect of energy, the difficulty of getting up steam, the easy and rapid 

 running down of the effort, if an effort is successfully initiated. 



There is another great type of functional disease — hysteria, so like 

 and yet so different from neurasthenia, which seems to be also a form of 

 chronic fatigue. 



