VARIETY IN PROTOPLASM 



307 



derived from one cell will be alike. The squash seed contains 

 protoplasm that is a combination of the protoplasm of the parent 

 plants. The protoplasm in the fertile egg of a frog is a part 

 and a continuation of the protoplasm of the parents of the frog. 

 Each kind of protoplasm continues to be much the same, genera- 

 tion after generation. 



There is no difficulty in recognizing maple trees, because all 

 maple trees resemble each other. Bean plants resemble bean 

 plants. Elephants resemble elephants. All the individuals of a 

 species are much alike. Yet no two individuals are ever exactly 

 alike. We might call by name and know several hundreds of the 



* EXAMPLES OF CHROMOSOME NUMBERS 



(in Animals and Plants) 



* Reprinted by permission from Wilson : The Cell in Development and Heredity (1925) by 

 The Macmillan Co. 



