( 125 ) 



3". Special oscillations of vo- 

 lume, which are longer and occur at 

 irregular periods; their cause is loss 

 clear. 



ngj 



Oscillations of the volume of the l)nüu 

 caused by pulsation and respiration 

 in half-sleep. 



a. tracing of the volume of the l)rain. 



h. tracing of the respiration. The des- 

 cending line is that of the inspiration. 



c. tuning fork. 2 vibrations per secoiul. 



(/. abscis. 



(L.4.URENS. June 18th 189S. Defect 

 of the scull caused by tuberculosis 

 of the OS parietale.) 



Figure I is an example of the two 

 first mentioned, in fig. II and III the 

 last mentioned are very clear. 



Whenever a sensation of sound 

 draws his attention, whenever the 

 person performs an intellectual pro- 

 cess, e.g. the solution of a sum, the 

 hyperaemia of the brain increases ; 

 it decreases as soon as the exer- 

 tion stops. The long last-mentioned 

 oscillations continue for some time 

 afterwards, to be of much greater am- 

 plitude and of much longer duration 

 than before the exertion took place (see 

 fig. III). On the other hand the oscil- 

 lations caused by respiration become 

 less visible during the exertion ; after 

 the exertion, however, they become 

 very distinct. 



At last the oscillation caused by 

 pulsation changes too. It becomes 

 quicker. Moreover the long oscillations 

 are influenced to a certain degree bv 



o -a ?i< a 



«^ 



