202 PHYSIOLOGY CHAP. 



Chauveau, disregarding the conclusions of Ceradiui (whom he 

 does not mention), maintains on the ground of obscure experiments 

 and complicated arguments, that the contraction of the papillary 

 muscles of the ventricles occurs during his " intersystole," with the 

 object of disposing the flaps of the auriculo-ventricular valves in 

 such a manner that the systolic rise in ventricular pressure (which, 

 according to him, brings about the valvular closure) may impinge 

 principally not upon the axial but upon the parietal face of the 

 valves. 



No long argument is required to demonstrate the impossi- 

 bility of this hypothetical doctrine. We know that the auriculo- 

 ventricular valves close at the termination of presystole. The 



FIG. 64. Tracings obtained by Chauveau from the horse, by his perfected cardiographic sound. 

 I, Oscillations of pressure in right auricle; II, oscillations of pressure in right ventricle; 

 r, return to abscissa ; 1, period of auricular beat (contraction and relaxation); _>, period of 

 intersystole ; 3, period of ventricular beat (contraction only). This is succeeded by the period 

 of ventricular diastole, which Chauveau does not indicate. 



supposed intersystolic contraction of the papillary muscles, 

 causing them to reopen, could not, even if it placed them in a 

 position unfavourable to the systolic reflux, entirely prevent it. 

 On the other hand, the researches of Eoy (1890) show that the 

 papillary muscles do not contract before the muscular walls of the 

 heart, but enter into tardy contraction, thus facilitating the almost 

 complete evacuation of the ventricles in systole. 



Tigerstedt's interpretation of Chauveau's intersystole, in the 

 fourth edition of his Pliysiologie des Menschen, seems no less 

 impossible. He thinks it depends on the elastic reaction of the 

 walls of the ventricles, which are passively distended in auricular 

 systole, and which occurs only in cases in which the termination 

 of the latter and the commencement of the ventricular systole are 

 separated by a considerable time interval. It is, in fact, sufficient 

 to look at one of Chauveau's curves, especially that of the internal 



