392 GENERAL NEUROSES, OF UNKNOWN ANATOMICAL ORIGIN 



des, and in part to surcharge of the blood with carbonic acid, in con- 

 sequence of spasmodic closure of the glottis. The fact that the loss 

 of consciousness and sensation and the occurrence of the convulsions 

 are almost always simultaneous ; and that the former sometimes pre- 

 cedes the latter ; and that in many cases of incomplete epilepsy it is 

 the sole symptom of the seizure, is a sufficient refutation of both hypoth- 

 eses. In like manner it must be declared that there is no proof as 

 to the truth of the theory of Schroeder van der Kolk^ that, in an epi 

 leptic fit, the ganglion-cells of the medulla excite a spasm of the vaso- 

 motor nerves of the brain, simultaneously with that which they induce 

 in the cerebro-spinal nerves, and thus cause cerebral anaemia and 

 palsy. So, too, with HenUs theory, which supposes the existence 

 of a plethoric and an anaemic form of epilepsy. He suggests that, in 

 the former, besides the more intense hyperaemia of the hemispheres 

 which induces the palsy, a lesser degree of hyperaemia, capable of in- 

 ducing symptoms of mere irritation, arises in the medulla oblongata ; 

 while, in the anaemic form, he imagines that the lack of blood in the 

 cerebral vessels occasions an increased blood-pressure upon the me- 

 dulla oblongata, inducing in it a degree of engorgement sufficient to 

 cause signs of irritation. Here, too, we shall refrain from further 

 theorizing, preferring to admit that to us the antagonism existing in 

 epilepsy, between the condition of the hemispheres and that of the 

 basilar portion of the brain, is entirely inexplicable. 



Owing to the scantiness of our knowledge as to the pathogeny of 

 epilepsy, the statistics regarding its predisposing and exciting causes 

 are of but secondary importance. We do not know of one single 

 agent of which we can certainly predict that it will produce epilepsy ; 

 yet, besides this, we must admit that all the assigned causes of this 

 disease by themselves are incapable of inducing it, and that the co- 

 operation of a second and unknown factor is always requisite. Statis- 

 tics show epilepsy to be a very common disease, about six epilep- 

 tics being found in every thousand individuals. Females suffer from 

 it somewhat more frequently than males. There is no age which is 

 completely exempt from it ; but the majority of cases occur between 

 the tenth and twentieth years of life ; next to this, between the sec- 

 ond and the tenth year, and between the twentieth and thirtieth year. 

 It seldom commences during old age, and its congenital occurrence, 

 as well as its appearance in the first months of life, is equally rare. 

 Hereditary predisposition plays an unmistakable part in its produc- 

 tion ; its existence is demonstrable in nearly a third of all cases. It 

 is especially apparent in persons descended from epileptic parents, par- 

 ticularly from epileptic mothers, as well as in individuals whose par- 

 ents or ancestors have been insane or intemperate. In some families 



