August 4, 1916] 



SCIENCE 



177 



parts which first manifest life are those which 

 die last. Harvey thought this to be true of 

 the blood, for he mistook the fibrillation of the 

 auricle in the otherwise quiescent heart for 

 an " obscure motion and flow and a sort of pal- 

 pitation manifestly ... in the blood itself," 

 and furthermore he observed that animals 

 without a pulse but which possess blood might 

 continue to live. 



Cause of the Heart Beat. — But Harvey was 

 not willing to attribute to his new-found pump 

 the importance which it deserved, as is seen 

 from his views in regard to the cause of the 

 heart's beat. To be sure, the most important 

 cause of the return of the blood to the heart is 

 the systole of the heart (and of the arteries) 

 which continually stuff with blood the porosities 

 of the parts. To this is added the muscular 

 movements of the limbs, etc., and in the case of 

 the pulmonary circulation the collapse of the 

 lungs. But when it comes to the dilatation of 

 the auricles the pump gives out and Harvey 

 finds it necessary to endow the blood with a 

 property (ebullition) borrowed from Aristotle. 

 This dilatation of the auricles is an event of 

 great importance to the circulation. Harvey 

 saw in it, as we shall see, the cause of the 

 heart beat. Aristotle knew nothing of contrac- 

 tility of muscle and was therefore obliged to 

 attribute not only the diastole of the heart, 

 but also its systole to the action of the blood 

 which boiled, rising and falling within the 

 heart. Since the time of Galen, however, the 

 power of contraction had been recognized in 

 muscle and consequently Harvey made use of 

 this doctrine in interpreting the action of the 

 heart. To Harvey the cause of the ventricular 

 beat was the mechanical distension of the ven- 

 tricle through the contraction of the auricle. 

 But what distended the auricle? The power 

 of ebullition of the hot blood (already referred 

 to) acting " in the vena cava close to the base 

 of the heart and to the right auricle." But 

 how, we ask, did Harvey explain the simulta- 

 neous contraction of both auricles and how did 

 he reconcile this view with the long-known 

 fact (often referred to by him) that excised 

 and bloodless hearts may continue to beat. In 

 regard to the first, he only remarked that the 



simultaneous movement of the two eyes is a 

 comparable phenomenon. But as to the second 

 he says nothing whatever. 



The Innate Heat. — Let us look more closely 

 at the nature of the " innate heat " and " the 

 soul " which Aristotle placed in the heart and 

 Harvey in the blood. Aristotle was convinced 

 that fire is sterile, while animal heat is gen- 

 erative and that therefore the heat of animals 

 is quite distinct from elemental fire. In the 

 simplest form of generation (the spontaneous) 

 the soul is derived from the air and the 

 heat from the sun. The solar heat is there- 

 fore generative and more akin to vital heat 

 than to fire. Again, in sexual generation 

 the vital heat and the soul are conveyed in 

 the semen, but nevertheless the solar heat 

 must be added " for the cause of man is his 

 father, the sun, and the ecliptic " (that is the 

 sun and its motions). The heat of animals is 

 analogous to the ether, the fifth and superior 

 element from which the heavenly bodies, in- 

 cluding the sun, are made. But strangely in- 

 consistent, he adds that the heat of the sun is 

 born of friction and is not ethereal. 



Harvey agrees with Aristotle that the ani- 

 mal heat is not fire nor derived from fire. He, 

 too, believed that the sun in its motions gen- 

 erates acting through the semen of the male, 

 that in generation the heat and soul are trans- 

 mitted in the semen but find their abode during 

 life not in the heart but in the blood. 



We have seen that Harvey was no mere 

 imitator of his great and revered master, 

 Aristotle, that he was an observer and thinker 

 of great originality and independence. It is 

 equally interesting to note in closing his atti- 

 tude toward the discoveries of others. The 

 Copernican astronomy he treated as still sub 

 judice. He paid no attention to the discovery 

 by Aselli of the lacteals. 



He did not care for Chymistrey and was wont to 

 speake against them (the chemists) with an under- 

 value. 



In rejecting the view of Columbus he lost 

 a valuable clue as to the nature of the respira- 

 tion. 



On reaching the end of this little volume one 

 is seized with regret not only that the book 



