402 EEYIEWS. 



simple, often slightly felt irritation of some centripetal nerve. He 

 brings what we conceive to be very ingenious and, at the same time, 

 valid, arguments in support of his novel view, that it is, occasionally, 

 by a reflex action of one part of the cerebro-spinal axis on another 

 part of itself, through the nerves going to the blood-vessels, that 

 irritation of one portion of the nervous centre acts in modifying, or 

 altering, the nutrition of another portion of itself. In this way he 

 offers an explanation of the attacks of epilepsy and epileptiform 

 seizures, resulting from organic lesion of the nervous centres. 



The researches of Dr. Brown- Sequard concerning the etiology 

 and nature of epilepsy are known to all the world, while his production 

 of artificial epileptiform attacks in animals as the result of lesion of the 

 spinal cord, and the very remarkable discovery that the offspring of 

 animals thus rendered epileptic frequently acquire, by hereditary de- 

 scent, the same affection, are facts no less interesting to the naturalist 

 than to the physiologist. But this subject which, with that of rotatory 

 convulsions, is discussed in his two final lectures, it is not our inten- 

 tion to enter upon : we shall content ourselves with observing that 

 they are lectures of great practical value, and show, in every line, the 

 extraordinary importance of studying, in all their varied aspects and 

 complex forms, the phenomena of reflex excitability. In reviewing 

 the principal of such phenomena, we cannot but admit that the best 

 physical explanation of them hitherto given, seems to be that through 

 the action of the vaso-motor nerves on the blood-vessels of the 

 nervous centres. Donders and his pupil Van der Beke Callenfels, 

 have shown the influence of these nerves directly on the vessels of the 

 pia mater ; and the experiments of Eussmaul and Tenner, although 

 coming from a different direction, are strongly confirmatory of 

 Brown-Sequard's views, and seem to those able experimenters to 

 justify them in asserting " that epileptic convulsions can be brought 

 about by contraction of the blood-vessels induced by the vaso-motor 

 nerves." A great number of observers have, of late, added new facts to 

 the physiology of the vaso-motor nervous system. But can we regard 

 the characteristic phenomena of epilepsy, or the still more subtle 

 forms of disease met with in insanity, vertigo, hallucinations, &c. as 

 entirely explicable by any such physical changes ? Must we not at 

 least still recognise the humoral views of Todd and such notions 

 as have been put forward by the original and ingenious Dr. 

 C. B. Badcliffe, as having their element of truth as a " vera causa" 

 in some cases? When we see a large snake struck across the tail 

 with a rod, and instantly, in the twinkling of an eye, seized with a 

 paralysis as complete as death, which yet, after a time, passes off again, 

 can we attribute such a condition to the constriction of the blood- 

 vessels of the cerebro-spinal axis ? We think not, because we know 

 that among these animals, the cerebro-spinal system does not (even 

 after the evacuation of the blood of the body) speedily cease to exercise 

 certain functions, and perform movements : and, moreover, we have 

 proved experimentally, that even after decapitation, a blow across 



