WHAT IS AN ORGANISM? l6/ 



special conditions, so the organic species may be looked upon 

 as a temporary thing made up of a certain number of actual 

 individuals, living at a particular time and under particular 

 circumstances, the individuality perpetuating itself by the 

 process of generation. But here the analogies cease, as is 

 explained elsewhere ; the incessant changing of the organic 

 form and function of the living organism distinguishes it 

 fundamentally from matter in any other condition. 



Growth and Reproduction of the Protozoa and of the Metazoa, 

 Contrasted. As will be seen from the above remarks, the 

 function of reproduction in the Metazoa is a specialization of 

 the simpler function of growth of the unicellular Protozoa. 

 Growth in the Protozoa seems to be limited by what may be 

 called the capacity of the organic cell, and reproduction then 

 consists merely in producing new cells, or in the multiplica- 

 tion of unicellular organisms. 



Generation the Fundamental Function of an Organism. In 

 the Metazoa the growth capacity is enlarged, and in these 

 higher animals reproduction or generation is no longer the 

 function of the whole organism, but is specialized off as a part 

 of its activity ; and in the structure of the organism special 

 parts, tissues, or organs are set apart or differentiated for 

 the execution of this special function. The remaining activi- 

 ties are spent in the development of the individual. Indi- 

 vidual development, and all auxiliary activities, have to da 

 with actually existing conditions of life, but generation looks 

 forward in its very essence to conditions that have not yet 

 appeared. Generation is, therefore, at the foundation of all 

 organic life and history, and in the process of generation organs 

 are constructed before they act, and independently of the exter- 

 nal environmeut to which they must be adjusted when they act. 



Summary of the Steps of Progress in Organic Development. 

 To summarize the steps of progress in the organic develop- 

 ment, we find, first, simple growth ; the cell increases by 

 absorbing matter from outside, accumulating it, and thereby 

 augmenting, both as to physical size and to the amount of its 

 organic force, whatever that may include. This process goes 

 on until the cell reaches the limit of its individual capacity, 

 until growth ceases. 



