313 



with meningitis one can often let all sjMnptoms disappear for a siiort 

 time by heightening the psychical level or by concentrating the 

 attention on something. The patient is then no longer confnsed, 

 gives the right answers, knows his bearings, and has no more 

 hallucinations. 



Moreover there is so strong a correspondance between normal 

 depressions of consciousness such as sleep and the dream, and the 

 acute pathological conditions of confusion, that of old a comparison 

 was readily made between these conditions. If now the low grade 

 of consciousness oi- the depression of the attentiveness is the cause 

 of the various symptoms of acute conditions of confusion, then it is 

 to be expected that such symptoms will also make their appearance, 

 albeit in rudimentary form, in normal and pathological conditions 

 in wiiich the grade of consciousness has sunk. 



To determine this I have made a series of investigations on persons 

 of whom it could with certainty be assumed thai the groups in which 

 they were classified w^ould show large ditFerences in attentiveness. 

 Among these weie patients with ol)vious intellectual disturbances, 

 sufferers from melancholia with strong obstruction and depression, 

 hysterics with a narrowed consciousness, and normal persons. After 

 the grade of consciousness had been determined by an examination 

 of the attentiveness, several other psychical functions, which are 

 more or less disturbed in acute conditions of confusion, were further 

 investigated. 



In a number of other subjects I limited this examination to a few 

 psychical functions only, viz. to the annihilation of weak impressi- 

 ons by later stronger ones. The results of this later examination I 

 shall mention immediately after d'escribing the arrangement of the 

 test, while the results of the first experiments, in which various 

 methods of examination have been used, will follow after a descrip- 

 tion of the methods has been given, so that in this way a better 

 survey is obtained for comparing the results. 



It is well known that there are many good methods for measuring 

 the voluntary attentiveness, which gives us an idea of the grade of 

 consciousness. I have made use of two of these viz. the Esthesio- 

 meter, which was first used by Griesbach ^) to determine fatigue, 

 and the marking method ') as this has been used in the determi- 

 nation of the psychical after-effects of school children. 



1) Griesbach Ueber Bezieliungen zwisclien geistiger Ermüdiing und Empfindings- 

 vermögen der Haul. Arch. f. Hygiene Bd. 24. 1895. 



2) VViERSMA. Psycliische Nachwirkungen. Zeitschr. fur de ges. Neur. u. Psych. 

 Bd. XXXV H 3. 



