100 WHAT IS LIFE 



ments in 1740, showing first of all that if the polyp 

 was cut into two pieces each of those two pieces 

 became a new and complete polyp. 



It was known, of course, at this time that 

 plants could be multiplied by a cutting process and 

 Trembley seems at first to have been undecided as 

 to whether he ought not to consider the hydra a 

 plant, because it also could be multiplied in this 

 way. However, his observations on its methods of 

 feeding and its power of movement brought him to 

 the conclusion that it was in truth an animal and 

 that his discovery revealed a new and hitherto un- 

 known power of animal life. " I felt," he says 

 with commendable modesty, " strongly that nature 

 is too vast, and too little known, for us to decide 

 without temerity that this or that property is not 

 found in one or another class of organised bodies." 

 Trembley continued his experiments, which have 

 constantly been repeated and verified in the years 

 which have passed since his death. He found that 

 a hydra could be divided into a number of pieces, 

 and that each bit would, under favourable circum- 

 stances, develop into a new and complete creature. 

 He also found that if the head-end was bisected, 

 the result was the formation of a two-headed hydra. 

 Moreover, he found that he could again and again 

 bisect these heads until he had an eight-headed 

 hydra with a single stalk or lower portion. It is 



