68 WHAT IS LIFE 



turning their hands to any job in the gradually 

 rising edifice of the body. 



A third and final experiment may be quoted, of 

 quite a different character. It was also carried out 

 by Wilson and is corroborated by other and similar 

 experiments on other forms. 



There is a little creature which lives in certain 

 seas and is known as the lancelet. To scientific 

 men, and now indeed to numbers of readers who 

 would not claim to be scientific, this creature is 

 better known as the amphioxus. In the course of 

 its development the single cell of which it was 

 originally formed divides into two-, four-, eight-, six- 

 teen-celled stages. 



Now let us suppose that at the eight-celled stage 

 the group is put into a test-tube with water and 

 violently shaken. The result is that the eight cells 

 are shaken apart and become completely separated 

 from one another. Then a very remarkable thing 

 happens. Most people would imagine that the im- 

 mature creature must have been killed by such 

 rough treatment, but such is not the "case. Each 

 of the eight cells, undaunted by what it has been 

 through, sets itself to work, begins to divide on 

 its own account and finally builds up a complete 

 amphioxus. Let us consider what this means. 

 A single cell, from the eight-celled groups, would 

 under normal circumstances have constructed, one 



