ON OPIUM. 355 



must haTe been extended over the entire sj'stem, by other EfFects of 



means than the circulation; for, what reason can be given pP*"™ °" t^* 



living systom. 



why the mass of fluids should not be altered, when the 

 solution was introduced by the crural as well as by the 

 jugular vein ; but upon the other theory, the solution of this 

 difficulty is easy, and accords with the whole series of ex- 

 periments. * 



The life of a rabbit cannot be sustained a minute without 

 the action of the heart ; when the solution of opium is in- 

 jected into the jugular vein, it is applied to the inward sur- 

 face of the heart, mixed with a very small quantity of blood, 

 and can then exert effects upon that organ as instantaneously 

 as if the heart was immersed in it, as in experiment 2d t, 

 the action of opium being thus directed against the irritable 

 fibre, the exhaustion of that part would immediately succeed, 

 of course the animal must die ; but when the same fluid is 

 injected into the crural vein, it does not reach the heart 

 until it has been mixed and diluted with a very considerable 

 portion of blood, so that no quantity of blood which the 

 heart could contain during one period of dilatation, would 

 be impregnated with any great quantity of the solution of 

 opium. The consequences therefore, which followed from 

 the injection of opium into the jugular vein, supposing 

 that it acted immediately on the heart, could not in this in- 

 stance he expected to take place. 



Does Opium act upon the Nervous Si/stem ? 

 Exp. 11. + A triangular piece of bone was taken from 

 the cranium of a frog, and the dura and pia mater removed; 

 eight drops of the strong solution were injected upon the 

 brain ; a few drops were lost. In one minute the animal 

 was convulsed, in three minutes it was dead. On exa- 

 mination the irritability in every part of the voluntary 

 muscles was destroyed, neither compression of the nerves 

 nor mechanical irritation could excite any contractions in 

 them. The heart had not lost its motion. 



* Vide Inaug. Dissert, p, 1 19. Note C. 

 t Vide Inaug. Dissert, p. 17. Exp. 14. 

 t Vide Inaug. Dissert, p. 49. Exp. 29. 



2 E 2 Exp. 



