4 THE HISTORY OF BIOLOGY 



to observe the heart-beat and to connect life with its continuance or cessa- 

 tion, and thus the heart itself was regarded as the organ of life. Breathing 

 was also observed to be an essential condition of life, and in particular the 

 deep expiration which indeed so often attends the actual moment of death 

 gave rise to the idea of life as having something of the nature of air, being 

 dependent upon the respiratory organs and leaving the body through them. 

 In medieval church paintings this belief reappears in a particularly naive 

 manner: the soul of the dying is seen to leave the body in the form of a little 

 child creeping out through the mouth. Likewise the words of the biblical 

 story of the creation to the effect that God breathed into man's nostrils the 

 breath of life testifies to the same kind of idea. And so there arose, as a fur- 

 ther development of these ideas, the belief that the breath or spirit lives 

 when the body dies. The contrast between body and spirit which is an out- 

 come of the ideas described above is included in the speculations of the earliest 

 natural philosophers as a fundamental principle. 



Kelationship to animals 

 However, in the mind of primitive man these lines of thought, proceeding 

 from the contrast between life and death, are crossed by others, which have 

 their origin in his relationship to the rest of the world of living creatures. 

 The great w'ld beasts — bears, lions, elephants — were difficult to overcome; 

 it was often necessary to try, as far as was possible, to make friends with 

 them. Other beasts were regarded with terror for their night-roving habits 

 and horrible cries, such as hyenas and owls; while some possessed otherwise 

 enviable natural gifts — the fox his cunning, the deer his swiftness, etc. 

 It is out of all this that we must explain the origin of the mass of animal 

 superstition that has filled the life of both wild and civilized peoples. As 

 forms in which this superstition has developed may be mentioned totem- 

 ism, or the custom existing among certain wild peoples of adopting animals 

 as a kind of guardian spirit and family symbol, as well as the belief in 

 and worship of holy animals, which, even amongst highly civilized peo- 

 ples, such as the Egyptians and the Romans, have played such an important 

 part in life. This animal superstition has naturally contributed towards 

 increasing the interest in and knowledge of animals, both as regards the 

 habits of life of those which were worshipped as gods, and the anatomy of 

 those which were offered in sacrifice and were most minutely examined 

 with a view to divining portents for the future from their internal structure. 



Primitive surgery and medicine 

 Finally, a third extremely important source of biological knowledge has 

 been medical science. Primitive surgery, which originated in attempts to 

 cure various bodily injuries, must of course eventually lead to a certain 

 amount of knowledge of the anatomy of the human body, a knowledge 

 which was increased by the process of comparison with the experience 



