304 NATURAL HISTORY OF ORGANIZED BODIES. 



To leave no doubt regarding the first proposition, I proceed to support it hy 

 experimental facts. It is in effect easy to demonstrate the necessity of the 

 sanguineous current in the exercise of a muscular action. Thus, when we tie 

 the lower aorta in an animal, we find that the muscles of the hind quarters are 

 quickly paralyzed. The same result follows if we inject into the arteries of a 

 limb a fine powder, which has the effect of obliterating the small vessels. M. 

 Flourens has shown that, under these circumstances, the nuiscles soon l)ecome 

 incapable of acting. There is a malady which veterinary surgeons call inter- 

 mittent claudication, and which has been attentively studied iu the horse by M. 

 Bouley and Dr. Charcot. This malady is produced by an obliteration of the 

 iliac arteries. In this state of things a new circulation is established l)y the 

 collateral vessels, but these have not the easy permeability of the large trunks 

 whose place they tend to supply. The animal thus affected can move for some 

 time in the usual way; but presently the afilux of blood to its muscles being no 

 longer sufficient, a sudden' parah'sis takes place and the horse stops. A moment 

 of repose re-establishes the muscular function, Avhich is exhausted anew after a 

 few steps. The case W'holly arises from the fact that the current of blood in the 

 muscles is no longer sufliciently rapid to maintain their function in a dnrable 

 manner. 



Again, let us take a frog in Avhich the vessels of one of the hinder feet have 

 been tied, and suppose that both feet have been excited by induced currents, 

 and that iu both the contractility has been fatigued by prolonged action. If we 

 now excite the two feet of the animal, it will be seen that the sound foot has 

 recovered its contractilit}^, while that whose vessels were tied still evinces in a 

 high degree the exhaustion consequent upon its fatigue. 



Granting then the necessity of a circulation so much the more rapid as the 

 muscular act is one of more energ}^ and duration, it is easy to prove the second 

 proposition which I just now advanced, namely : that this muscular act commu- 

 nicates of itself a greater rapidity to the circulation of the blood. Every.one 

 is aware that in venesection, if the member is motionless, the blood escapes 

 slowly from the vein, while the flow becomes much more cojjious if the patient 

 exerts contractions of the muscles of the fore-arm. The question hero is nut 

 that of a simple comj)ression of the veins by the muscles, which would mechani- 

 cally express the blood contained in those vessels. Such a cause would speedily 

 have exhausted its eflect, and extruded but an inconsiderable quantity of blood. 

 There is exerted, on the contrary, a continuous action which accelerates the 

 course of the blood as long as the contractions (^f the muscles of the foi'e-arm are 

 continued. A still more convincing demonstration of the influence of the muscu- 

 lar act on the current of the blood may be given, b}' showing that the arterial 

 system is depleted iu an animal which has just desisted from running and presents 

 in its interior a more feeble pressure than in a state of rejiose.* From such 

 facts as these it results that the nuisculiir act operates on the circulation in such 

 a way as to accelerate the course of the blood through the muscles, and thus 

 ])romotes that action by wdiich the acceleration was occasioned. 



We might cite a great number of examples of this law of harmony of the 

 functions, and show, for instance, that the venous blood, Avhen it arrives in 

 abundance at the lungs, stimulates that organ and provokes the respiratory 

 movements destined to arterialize it, while the respiration, at the moment when 

 it is executed, opens a passage for the blood on which it is to act, &c. But 

 these reciprocal inffuences of the functions wottld exact too long developments 

 to be thoroughly treated on this occasion. I confine myself to a notice of the 

 existence of this law of liarmony oi which I have been speaking, the recognition 

 of which I consider of the greatest utility, as enabling us often to foresee pheno- 

 mena which experiment will verify. 



* See, for further development of this subject, Marey, Physiulogie mtdicale de la circula- 

 tion du sang, p. 223, Paris, ltiC3. 



