576 



PHYSIOLOGY 



CHAP. 



1 to 2 C. during an attack of epilepsy ; and in the epileptic state 

 the temperature may reach 44 C. The rise of temperature during 

 the fits is certainly in relation with the intensity and spread of 

 the muscular convulsions. 



When the cerebral cortex, either from individual predis- 

 positions, or from special conditions due to the operation, is in a 

 state of abnormally increased excitability, an epileptic attack may 

 be reflexly excited by stimulation of a sensory nerve (FranQois- 

 Franck). Under ordinary conditions stimulation of the inex- 

 citable parts of the brain cannot induce an epileptic attack, but 

 if the motor area, i.e. the whole or certain of the excitable parts 

 are in a state of hyper-excitability, owing to exposure to the air or 



FIG. 294. M, epileptoid fit, tracing from muse, extensor cruris. (Franc,ois-Franck and Pitres.) 

 The fit falls into three periods ; 1, a tonic period, corresponding to the duration of the electrical 

 excitation E ; 2, at the close of cortical stimulation, the tetanic condition is reinforced ; 3, the 

 donic period, in which the muscle gradually relaxes. 



to previous stimulation, application of the faradic current to the 

 cortex of the occipital or parieto- temporal lobe (i.e. to points 

 more or less remote from the motor area) may also evoke an 

 epileptic fit. Does this fact depend on physical conduction of the 

 current to the hyper-excitable region, or have areas become hyper- 

 excitable which do not normally respond to artificial stimuli ? 

 The latter supposition agrees with the fact that spontaneous 

 epilepsy (whether idiopathic or Jacksouian) is generally preceded 

 by a sensory aura which varies in character, and is evidently due 

 to excitation of different sensory areas of the cortex. It is im- 

 portant to note that in Jacksonian seizures, unlike even the 

 mildest form of idiopathic epilepsy, the attack is accompanied by 

 a disturbance, but never by complete loss, of consciousness. 



By means of a tracing on a rotating drum from one muscle of 

 a limb, Fran9ois-Franck and Pitres were able to investigate the 

 muscular phenomena of the epileptic fit produced by electrical 



