54 LUTHER BURBANK 



based on mechanical and chemical change. In 

 nature we find varied animate and inanimate 

 forms of life, many of which have motions — 

 some of which in the higher forms we call emo- 

 tions. These sometimes end in action, at other 

 times in thought. 



By common consent we usually associate life 

 as commencing with the unit of life — the indi- 

 vidual cell — but life really exists as an organized 

 force in all growing crystals and in a review of 

 the fundamentals of life we must go even to a 

 more primitive form than that of crystal life; 

 below even these we find, instead of the organized 

 growth seen in crystals, an amorphous life. The 

 substances called colloids have no definite struc- 

 ture like crystals, yet they respond to some of 

 the same forces which act upon crystals and upon 

 individual unit cells. These colloidal substances 

 have no very well defined visible structural forms 

 like crystals, yet some of the lowest forms 

 of animal life, hke the amoeba, are almost as 

 indefinite in form and structure; in fact, having 

 no more definite form than a piece of soft putty 

 or a passing cloud; just a mass of jelly, yet able 

 to perform all the functions and motions neces- 

 sary to animal life in its primitive state. 



Both crystals, the amoeba and other unicellular 

 forms, respond definitely to some of the forces 



