733 



Fellow of the Royal College of Surgeons of England. Communicate 

 by P. M. Roget, M.D., Sec. R.S. 



The following abstract of this paper has been drawn up by the 

 author. 



The author endeavours to prove, by inductive reasoning and by 

 historical considerations of the earliest indication of vitality in the 

 egg, that motion of a fluid in a certain definite circle constitutes the 

 ■first link in the chain of causes by which vitality is perfected ; that 

 all the other phenomena of living structure are supplementary and 

 superinduced upon this primary and indispensable condition; and that, 

 although it might be possible to maintain this primary circulation 

 under certain circumstances, even though all the other functions of 

 life were suspended or destroyed, they, on the contrary, cannot exist 

 independently of that circulation. He shows it to be necessary to 

 circulation, that two fluids, or a fluid in two dififerent states, should 

 communicate by two points or extremities with each other, and that 

 these extremities should present such a resistance to their mutual 

 connexion and commixion, that the transfer of conditions of each, 

 from one to the other, must take place, otherwise the uniformity of 

 both would speedily put an end to the process ; and it is indicated 

 that the forces in operation in these two places would be reverse to 

 each other ; in the one it would be from arterial to venous, and in 

 the other from venous to arterial. 



The blood-vessels containing the two kinds of blood are com- 

 pared by the author to two bar- magnets placed side by side, the 

 pulmonary and systemic capillaries representing the armatures placed 

 at their extremities ; with this limitation, that as the changes in 

 the blood take place only in the two opposed sets of capillaries, 

 the force is necessarily generated only in them, and therefore the 

 intermediate blood contained in the larger blood-vessels merely re- 

 presents conducting wires completing the circuit. The left side of 

 the heart is viewed as being placed in the largest ampulla of the arte- 

 rial circulation, and the right side of the heart as being in the like 

 position with respect to the venous current. 



The portal circulation- is alluded to, in order to prove that a pro- 

 pelling force is not essential to produce circulation of blood. An 

 account is given of numerous experiments on various animals, in 

 which the ends of two similar wires (in some cases of copper and in 

 others of platinum) were inserted ; that of the one into a vein, and 

 that of the other into an artery, the free ends of both wires being 

 brought into connexion with a delicate galvanometer ; and it was 

 found that during life a galvanic current was indicated, passing along 

 the artery and returning by the vein ; that this current became more 

 feeble in proportion as the vitality of the animal declined, and again 

 more strong as the effect of the chloroform, which was administered 

 for the i)urpose of preventing pain, subsided. 



The author also observed, that the strong action of a muscle (the 

 sterno-mastoid) between the two blood-vessels tended to discharge 

 the galvanic force as it was generated ; and that when that muscle 

 was divided, the galvanic force became much stronger. When the 



