34 THE SMALLEST LIVING THINGS 



differences, which, however, cannot be detected chemically, have 

 to do, in all probability, with specific differences in the proteins. 

 In the same environment a given fundamental organization 

 invariably develops the same types of structures and in the same 

 order, and such structures, coming from the fundamental organi- 

 zation are included in what we call the derived organization 

 (see page 38). The derived organization of a species is seen 

 in its best development in the adult organism. The fundamental 

 and the derived organizations constitute the working parts of 

 the infinitely complex aggregate which we call a living thing; they 

 make up the "organization" of living matter, and such organi- 

 zations are as varied as there are types of cells of animals and 

 of plants. 



Vitality 



Vitality is the term used to express the activity of the proto- 

 plasmic constituents of the organization. The numerous sub- 

 stances found in protoplasm, be they temporary or permanent 

 in nature, are constantly acting and reacting with one another 

 and with other substances by which they are surrounded in the 

 environment, in both chemical and physical fashion. Neverthe- 

 less, they must maintain a state of balanced equilibrium or be 

 capable of quickly re-establishing an equilibrium; if otherwise, 

 protoplasm would disintegrate. One means of maintaining this 

 balance or equilibrium is the presence of living membranes, not 

 only about the cell, but also about the nucleus and by lipoid 

 (fat-like) membranes about the colloidal particles. These mem- 

 branes regulate permeability (the passage of substances in and 

 out), while the speed of chemical reactions is hastened by elusive 

 chemical substances — the catalyzing and the synthesizing 

 enzymes.* 



Encystment and the Fundamental Organization 



The concepts outlined above — organization and vitality — 

 representing the complicated and interrelated parts of an organ- 

 ism and the equally complicated and interrelated activities of 

 those parts, give us a basis for an estimate of the nature of life, 



* See the Glossary of this book, page 120. 



