286 



unexpected sight of an object, the disagreeable impression occasioned 

 by certain odours, 8cc. In all these cases, there is felt, in the region of 

 the diaphragm, an inward sensation of a certain degree of emotion. From 

 the solar plexus of the great sympathetic nerve, which, according to the 

 general opinion, is considered as the seat of this sensation, its effects ex- 

 tend to the other abdominal and thoracic plexuses. The heart, the great- 

 er part of whose nerves arise from the great sympathetic, is particularly 

 affected by this sensation. Its action is, at times, merely disturbed by it, 

 and at other wholly suspended. The pulse becomes insensible, the coun- 

 tenance pale, the extremities cold, and syncope ensues. This is the course 

 of things, when a narcotic or poisonous substance has been taken into 

 the stomach; when this viscus is much debilitated, in consequence of 

 long fasting, or when it contains indigestible substances; in colic, and in 

 hysterical affections. 



The last class of occasional causes do not act directly, and produce 

 syncope only at a distant period; but the result is always the same. It 

 happens, in all the cases, that as the arteries of the head no longer receive 

 as much blood as in health, the brain falls into a kind of collapse, which 

 occasions a momentary cessation of the intellectual faculties, of the vital 

 functions, and of voluntary motion. 



Morgagni, in treating of diseases, according to their anatomical order, 

 ranks lypothymia among the affections of the chest, because the viscera 

 contained in that cavity, show marks of organic affection, in persons who, 

 during life,, were subject to frequent fainting. 



The compression of the brain, by a fluid effused on the dura mater, in 

 \vounds of the head, does not produce real syncope, but rather a state of 

 stupor. All causes, acting in this manner on the brain, produce coma- 

 tose and even apoplectic affections. When a man, on being exasperated, 

 falls into a violent and ^sudden fit of passion, his face becomes flushed, 

 and he is affected with vertigo and fainting. There is no loss of colour, 

 no loss of pulse; the latter, on the contrary, generally boats with more 

 force. This is not syncope, but the first stage of apoplexy, occasioned 

 by the mechanical pressure on the brain, towards which the blood is car- 

 ried suddenly and in too great a quantity. 



I might support this theory of syncope, by additional proofs drawn 

 from the circumstances which favour the action of the causes giving rise 

 to affections of this kind. For instance, syncope comes on, almost al- 

 ways, when we are in an erect posture; and in such a case, it is right to 

 lay the patient in a horizontal posture. Patients debilitated by long dis- 

 eases, taint the moment they attempt to rise, and recover on returning 

 to the recumbent posture. Now, how are we to explain this effect of 

 standing, in persons in whom the mass of humours is much impoverished, 

 and whose organic action is extremely languid, unless by the greater dif- 

 ficulty to the return of the blood, from the more depending parts, and on 

 the difficulty in ascending, of that which the contractions of the heart 

 send towards the head ? The phenomena of the circulation, are, under 

 such circumstances, more subject to the laws of hydraulics, than when 

 the body is in a state of health ; the living solid yields more easily to the 

 laws of physics and mechanics, and, according to the sublime idea of the 

 father of physic, our individual nature approaches the more to universal 

 nature. 



CXLVIII. Of the motions of the brain. Are the alternate motions of 

 elevation and depression seen, when the brain is exposed, exclusively 



