374 THE WONDER OF LIFE 



Thus the hfe of the organism is very different from the 

 path of a rocket in the air, which spends itself wholly in 

 its brilhant career, for normally the organism has offspring. 

 The vital trajectory is different from the course of the 

 drops of water in a fountain, which rise to the summit, 

 sparkle a moment in the sunhght, and sink again to earth. 

 The organism secures the continuance of its kind. 



The Wonder of Development. — There are some 

 beautifully transparent eggs which we can watch as they 

 develop, actually witnessing the divisions and displace- 

 ments of cells. The egg of one of the moths, Botys 

 hiemalis, is a good illustration, and there are few pro- 

 cesses that go on in the world more impressive than this 

 development — the emergence of the obviously complex 

 from the apparently simple. In the case of the hen's 

 egg, that we are so familiar with, a small drop of 

 transparent living matter lies like an inverted watch- 

 glass on the top of the ball of yolk. From that drop, in 

 the course of three weeks, the chick is built up — the most 

 familiar fact in the world and surely wonderful. In his 

 forty-ninth Exercitation on ' the efficient cause of the 

 chicken,' Harvey quaintly expressed his sense of the 

 wonder : — 



' Although it be a known thing subscribed by all, that 

 the foetus assumes its original and birth from the male 

 and female, and consequently that the egge is produced 

 by the cock and henne, and the chicken out of the egge, yet 

 neither the school of physicians nor Aristotle's discerning 

 brain have disclosed the manner how the cock and its seed 

 doth mint and coine the chicken out of the egge.' 



Development is the ' becoming ' of the individual 

 organism. It is the attainment of a specific form and 



