436 THE CIRCULATION OF THE BLOOD 



has seen a recently killed animal opened knows that these 

 two kinds of tubes to which I have just referred, are con- 

 nected with an apparatus which is placed in the chest, 

 which apparatus, in recently killed animals, is still pulsating. 

 And you know that in yourselves you can feel the pulsation 

 of this organ, the heart, between the fifth and sixth ribs. 

 I take it that this much of anatomy and physiology has been 

 known from the oldest times, not only as a matter of 

 curiosity, but because one of the great objects of men, from 

 their earliest recorded existence, has been to kill one another, 

 and it was a matter of considerable importance to know 

 which was the best place for hitting an enemy. I can 

 refer you to very ancient records for most precise and clear 

 information that one of the best places is to smite him 

 between the fifth and sixth ribs. Now that is a very good 

 piece of regional anatomy, for that is the place where the 

 heart strikes in its pulsations, and the use of smiting there 

 is that you go straight to the heart. Well, all that must 

 have been known from time immemorial at least for 

 4,000 or 5,000 years before the commencement of our era 

 because we know that for as great a period as that the 

 Egyptians, at any rate, whatever may have been the case 

 with other people, were in the enjoyment of a highly 

 developed civilisation. But of what knowledge they may 

 have possessed beyond this we know nothing ; and in 

 tracing back the springs of the origin of everything that 

 we call " modern science " (which is not merely knowing, 

 but knowing systematically, and with the intention and 

 endeavour to find out the causal connection of things) I say 

 that when we trace back the different lines of all the modern 

 sciences we come at length to one epoch and to one country 

 the epoch being about the fourth and fifth centuries 

 before Christ, and the country being ancient Greece. It is 

 there that we find the commencement and the root of every 

 branch of physical science and of scientific method. If we 

 go back to that time we have in the works attributed to 

 Aristotle, who flourished between 300 and 400 years before 

 Christ, a sort of encyclopaedia of the scientific knowledge of 

 that day and a very marvellous collection of, in many 

 respects, accurate and precise knowledge it is. But, so far 

 as regards this particular topic, Aristotle, it must be con- 

 fessed, has not got very far beyond common knowledge. 

 He knows a little about the structure of the heart. I do 

 not think that his knowledge is so inaccurate as many 



