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effects of paralysis or excitation of the sympathetic nerve on blood- 

 vessels ? We entirely concur with the answer given to this question 

 by Dr. Brown- Sequard, that facts discovered by Ludwig, by Czermak, 

 and especially by Claude Bernard, seem to have solved the question 

 in the most positive manner, and that it seems absolutely certain 

 that there is some agency of the nervous system, which is not simply 

 an influence on the constricting muscular fibres of blood vessels, in 

 the normal, or pathological, phenomena of secretion and nutrition. 

 Professor Bernard has pointed out, how that, instead of contracting, 

 the blood-vessels of the salivary glands become enlarged, when certain 

 nerves are excited. To explain this and other, apparently contra- 

 dictory, facts, we must seek for some theory embracing a wider gene- 

 ralization than any hitherto propounded. As we have already said, 

 the notion of Dr. Brown- Sequard that this enlargement in the blood- 

 vessels must be due to a greater attraction of the arterial blood by 

 the tissue of the gland, seems to us a mere change of terms, explain- 

 ing nothing. Indeed it leaves physiology as regards these pheno- 

 mena in very much the same position as did Prochaska, whose obser- 

 vations on " the action of nerves on vessels and their fluids" are both 

 interesting and instructive. 



" Another function of the nerves," says this most acute observer, " consists in a 

 certain power over the blood-vessels, and specially the capillaries, in virtue of which, 

 when the nerves are stimulated (?) they excite, in that part in which they are dis- 

 tributed, a much more copious accumulation of blood than would have taken place 

 in the normal condition of the circulation. Stahl termed it the tide of the micro- 

 cosmic sea, or the ebb and flow of the blood — one cause of it is a stimulus of the 

 nerves. Innumerable phenomena of daily occurrence shew this. Thus a stimulus 

 to the nerves is the cause why the cheeks, ears and nose become intensely red and 

 a sense of heat is felt, when exposed to a cold wind in winter. No one is ignorant 

 how much the stimulus of sinapisms and blisters causes derivation to the stimulated 

 part ; an acrid smoke, or fine powder, getting into the eyes excites a copious flow 

 of tears, and the vessels of the conjunctiva, previously invisible, become distended 

 with blood. The smoke of tobacco or any other acrid aroma, retained in the 

 mouth, excites a copious flow of saliva, &c. &c. But the same thing happens when 

 the nerves are excited not direct!// but indirectly through the brain. We know 

 that the face is suffused with the blush of modesty ; grief causes a copious flow of 

 tears, congestion of the vessels of the conjunctiva, and redness and swelling of the 

 whole face. The sight of agreeable food provokes the flow of saliva ; it is not 

 unusual for some persons to vomit, or be purged, by only seeing a medicine, &c. &c. 

 ])oes not the vis 'nervosa, increased by a stimulus, render the force of attraction of 

 the fluids circulating through the vessels greater, so that by this means the fluids 

 are attracted from every side to the centre of stimulation, as occurs, for example, 

 when scaling wax is gently rubbed on a piece of cloth, and made electrical, and 

 attracts sand and particles of various kinds." 



Modern physiology will hardly be content to answer this ques- 

 tion in the affirmative ; to us it would seem as unsatisfactory as the 

 supposition of active dilatation of the blood-vessels. . . . Although 

 to our mind the solution given to the question, how a reflex action 

 may produce or stop a secretion, how it may produce an atrophy or 

 an hypertrophy, an inflammation or some other change in nutrition, 

 by Dr. Brown- Sequard, is in some respects not more satisfactory than 



