A HISTORY OF SCIENCE 



a justifiable inference that the first conception primi- 

 tive man would have of his own life would not include 

 the thought of natural death, but would, conversely, 

 connote the vague conception of endless life. Our own 

 ancestors, a few generations removed, had not got rid 

 of this conception, as the perpetual quest of the spring 

 of eternal youth amply testifies. A naturalist of our 

 own day has suggested that perhaps birds never die 

 except by violence. The thought, then, that man has a 

 term of years beyond which "in the nature of things," 

 as the saying goes, he may not live, would have dawned 

 but gradually upon the developing intelligence of suc- 

 cessive generations of men; and we cannot feel sure 

 that he would fully have grasped the conception of a 

 "natural" termination of human life until he had 

 shaken himself free from the idea that disease is always 

 the result of the magic practice of an enemy. Our 

 observation of historical man in antiquity makes it 

 somewhat doubtful whether this conception had been 

 attained before the close of the prehistoric period. If 

 it had, this conception of the mortality of man was one 

 of the most striking scientific inductions to which pre- 

 historic man attained. Incidentally, it may be noted 

 that the conception of eternal life for the human body 

 being a more primitive idea than the conception of 

 natural death, the idea of the immortality of the spirit 

 would be the most natural of conceptions. The im- 

 mortal spirit, indeed, would be but a correlative of the 

 immortal body, and the idea which we shall see preva- 

 lent among the Egyptians that the soul persists only 

 as long as the body is intact the idea upon which the 

 practice of mummifying the dead depended finds a 



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