634 THE WONDER OF LIFE 



how many times winter has frozen it. ... A living being 

 must always contain within itself the history, not merely 

 of its own existence, but of all its ancestors.' 



As Bergson maintains, it is distinctive of the organism, 

 as of ourselves, that : 



' Its past, in its entirety, is prolonged into its present, 

 and abides there, actual and acting '. ' Continuity of 

 change, preservation of the past in the present, real dura- 

 tion the living organism seems to share these attributes 

 with consciousness '. 



Argument from Development. When we observe 

 the development of an animal actually going on, in almost 

 perfect transparency, as in the moth Botys hyalinalis, we 

 get an impression of something very unlike anything else in 

 the world. From a minute clear drop of living matter 

 lying on the top of the yolk we see in the course of twenty- 

 one days the development of the chick the gradual emer- 

 gence of the obviously complex from the apparently simple. 

 It seems far away from mere machinery ; it is more like 

 an artist painting a picture. We get the same impression 

 when we look into details, such as the making of the silk- 

 like threads that compose the familiar skeleton of the bath 

 sponge. Large numbers of secretory cells called spongo- 

 blasts group themselves in double file in the middle 

 stratum of the sponge, as if some unseen captain mar- 

 shalled them. Up the middle of the double file spongin 

 is secreted, made at the expense of the contributors, and 

 the many individual contributions coalesce in a sponge- 

 fibre. By combining the images that we get from sections 

 at various stages we can, in a sense, see the replacement 

 of a piece of cartilage by bone the sappers and miners 



