THE LAW OF BIOGENESIS 73 



nourished and protected by the body of the plant 

 or animal, and periodically becoming active, some 

 once in twelve months, others once every month. 

 In most plants and all of the lower animals, re- 

 productive activity is seasonal. This is especially 

 apparent in many of the sea forms which grow 

 elaborate bodies whose sole work, seems to be the 

 production of germ cells. As soon as this great 

 task is complete, they droop, wither and die — a 

 fact strikingly shown in such simple animals as the 

 hydroids which are related to the jelly-fishes and 

 corals. These beautiful plant-like forms attain to 

 a luxuriant growth in June and July along our 

 Northern Atlantic coast, producing great quanti- 

 ties of germ cells. After these are set free, the 

 parent organisms waste away and disappear. In 

 the simple forms of plants and animals the pro- 

 duction of new individuals is the supreme act of 

 life. 



The power to form new individuals like the 

 parent or parents is a universal feature of living 

 things. The animal or plant that cannot do this 

 becomes extinct and all that can be said of it is 

 that it once lived. Instead of reproduction some 

 writers use the term "instinct for perpetuation." 

 Reproduction is one of the fundamental character- 

 istics of living protoplasm that in some instances 

 becomes so complex that special terms are needed 

 to describe the process. Without this power to 



