14 ON THE HEART AND BLOOD. 



cisely the same as in the other arteries, and yet it has no proper 

 arterial tunic. This the learned Riolanus testifies to, along with 

 me, in his Seventh Book. 



Nor let any one imagine that the uses of the pulse and the 

 respiration are the same, because under the influence of the same 

 causes, such as running, anger, the warm bath, or any other 

 heating thing, as Galen says, they become more frequent and 

 forcible together. For, not only is experience in opposition 

 to this idea, though Galen endeavours to explain it away, when 

 we see that with excessive repletion the pulse beats more forcibly, 

 whilst the respiration is diminished in amount ; but in young 

 persons the pulse is quick, whilst respiration is slow. So is it 

 also in alarm, and amidst care, and under anxiety of mind ; 

 sometimes, too, in fevers, the pulse is rapid, but the respiration 

 is slower than usual. 



These and other objections of the same kind may be urged 

 against the opinions mentioned. Nor are the views that are 

 entertained of the offices and pulse of the heart, perhaps, less 

 bound up with great and most inextricable difficulties. The 

 heart, it is vulgarly said, is the fountain and workshop of the 

 vital spirits, the centre from whence life is dispensed to the se- 

 veral parts of the body ; and yet it is denied that the right ven- 

 tricle makes spirits ; it is rather held to supply nourishment to 

 the lungs; whence it is maintained that fishes are without any 

 right ventricle (and indeed every animal wants a right ventricle 

 which is unfurnished with lungs), and that the right ventricle 

 is present solely for the sake of the lungs. 



1. Why, I ask, when we see that the structure of both ven- 

 tricles is almost identical, there being the same apparatus of 

 fibres, and braces, and valves, and vessels, and auricles, and in both 

 the same infarction of blood, in the subjects of our dissections, of 

 the like black colour, and coagulated why, I say, should their 

 uses be imagined to be different, when the action, motion, and 

 pulse of both are the same ? If the three tricuspid valves placed 

 at the entrance into the right ventricle prove obstacles to the re- 

 flux of the blood into the vena cava, and if the three semilunar 

 valves which are situated at the commencement of the pulmonary 

 artery be there, that they may prevent the return of the blood 

 into the ventricle ; wherefore, when we find similar structures in 

 connexion with the left ventricle, should we deny that they are 



