304 NATURAL HISTORY OF ORGANIZED BODIES. 



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

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

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

 thelower 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. 

 Flonrens has shown that, under these circumstances, tlie muscles soon become 

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

 mittent claudication, and Avhich has been attentively studied in 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 by the 

 collateral vessels, but these have not the easy permeabilitv 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 afflux of blood to its muscles being no 

 longer sulhcient, a sudden paralysis takes place and the horse stops. A moment 

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

 few steps. The case wholly arises from the Ibct that the current of blood in the 

 muscles is no longer sufficiently rapid to maintain llieir function in a durable 

 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 in both the contractility has been fatigued by prolonged action. If we 

 now excite the two feet of the animal, it will 1)6 seen that the sound foot has 

 recovered its contractility, while that whose vessels were tied still evinces in a 

 high degree the exhaustion conseciuent upon its fatigue. 



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

 muscular act is one of more energj^ 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 rai)idity 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 copious if the patient 

 exerts contractions of the muscles of the fore-arm. The question here is not 

 that of a simple compression of the veins hy the nurscles, which would mechani- 

 cally express the blood contained in those vessels. Such a cause wt)uld speedily 

 have exhausted its effect, and extruded but an inconsidei'able quantit}' of blood. 

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

 course of the blood as long as the contractions of the muscles of the Jbre-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, Ijy showing that the arterial 

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

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

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

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

 pr(»motes that action by which the acceleration was occasioned. 



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

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

 abundance at the lungs, stinmlates 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 

 tliese reciprocal influences of the functions would exact too long developments 

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

 existence of this law of liarmoni/ 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 dcvelopuient of this subject, Marey, Physiologie medicale de la circula- 

 tion dii sanrr, p. 2vJ3, Paris, 1^63.. 



