RELATIONS OF ABNORMAL PSYCHOLOGY 739 



mind which have been brought to light by pathological psycho- 

 logy, has called attention to a group of phenomena which can 

 scarcely be classified among the older faculties, and have been 

 neglected as being of no significance the phenomena of fatigue, 

 of sleep, of the emotions, of the various forms of intoxication, of 

 the neuropathic disorders. It has also called attention to the oppo- 

 site modifications which occur in repose, in the waking state, in 

 calmness and sang froid, and in convalescence (even though it be 

 but temporary). These modifications constitute the most apparent 

 oscillations of mind. Permit me to lay emphasis upon these de- 

 pressions and these excitations, and to remind you of the inves- 

 tigations which have been made in this connection. These topics 

 are of even greater significance; they represent the most import- 

 ant of the present problems of pathological psychology. 



One of the first modifications of mental states to which I wish 

 to call attention, is illustrated by the semi-normal, semi-patho- 

 logical condition which is induced by fatigue. It is a familiar fact 

 that the physical and mental being does not always maintain a 

 constant condition; that it is incapable of manifesting uniform 

 phenomena when submitted to prolonged effort; that its func- 

 tions vary from the beginning to the end of a period of work. And 

 the change induced is essentially of the same character whether 

 the work be physical or mental. The investigation of mental 

 fatigue dates from an early period. You doubtless recall an old 

 observation by Holland which has been cited by Ribot. 1 "An engin- 

 eer relates the following experience: 'When I was down in a 

 mine, I felt myself overcome by fatigue and lassitude to such a 

 degree that I found it impossible to converse with the German 

 inspector who accompanied rne. Every word, every phrase of the 

 German language had escaped my memory, and I recovered them 

 only after taking nourishment and rest.'" Here we have a first 

 well-marked opposition between the normal state and the state 

 of fatigue. Oppositions of this sort have been the object of numer- 

 ous investigations, among which may be mentioned Galton's in- 

 teresting study of the influence of fatigue and overwork in schools, 

 the investigations of a great many German authors, instigated 

 for the most part by Kraepelin, the remarkable observations of 

 the French physician Tissie", who made a physiological and psych- 

 ological examination of the contestants in various forms of ath- 

 letic sports, the investigations of Fe"re\ of Binet and Henri, etc. 

 All of these investigations show the presence of modifications of 

 constant character. 



It is to be noted, first of all, that an apparent exaggeration of 

 1 Ribot, Maladies de la M&moire, p. 114. 



