150 PHYSIOLOGY OF MICROORGANISMS 



phasize the possible extension of the simple and even rudimentary 

 basic facts to the field of general physiology. 



The complicated structures of the metazoa and metaphytes can 

 scarcely be compared with microorganisms. It is difficult to speculate 

 intelligently on the development of shape and structures in biological 

 forms in the light of present knowledge, yet proceeding from simple 

 forms to the more complex, there is constantly confronting the mind 

 the possibility on the part of nature to adjust form and structure to the 

 growing and expanding demands of protoplasm. The struggle on the 

 part of a microorganism to secure oxygen or to get away from it, the 

 action of light and darkness on the growth of molds and other factors 

 signify as much to a simple single-celled organism as the prehensile 

 tendencies of an insect or an ape. It is something sought by the use of 

 different structures and of different agents. There are so many 

 indications of incipient developments in the unicellular organism that 

 much time and space could be given to speculative possibilities. Only 

 a suggestion is required, however, to start the thinking student to 

 fruitful reflection. The morphologist approaches the subject of the 

 place of microorganisms in nature through the channels of " degenerated 

 forms" from "higher forms" or " types of simple forms in process of 

 evolution." This view does not harmonize with the physiological 

 approach in which functioning supercedes form unless degeneration 

 and evolution is made a matter of functioning instead of form. 



A cell as a free unit and a cell as a unit but tied into a community 

 of cells awaken interest. The free cell might be likened to primitive 

 man, a Jack-of-all-trades, but a cell interwoven into a multicellular 

 organism is that of a Jack-of-all-trades, an individual, and a man in a 

 social organization, a specialist. This seems to be apparently true 

 except where the cells simply form an aggregation or a colony in which 

 all cells function alike. There is, too, the tendency of the single free 

 cell to specialize as those of the alcoholic group, the lactic group and 

 many others. To say that they are in the process of functioning to- 

 gether in an organism as the yeast and acetic organisms is wholly 

 chimerical yet very suggestive in nature's slow evolutions. Few facts 

 can be brought forward to disentangle definitely such conceptions. 



As a working basis to-day it is necessary, because of restricted 

 human advancement, to consider the cell as the unit of life although its 

 compositional structure when understood may reveal the unit of life 

 for to-morrow. 



