148 PHYSIOLOGY OF MICROORGANISMS 



bound up with other cellular life that it ceases without such association, 

 whether it is regarded from the standpoint of individual entities, the 

 protophytes and the protozoa, or the standpoint of the complex entities, 

 the metaphytes and metazoa. Virchow made the cell the working unit 

 system of life, but it was done in the sense that the " House of Roths- 

 child" has become a unit in the financial world. Pfliiger, Verworn, 

 Ehrlich and Vaughan, however, resolve the cell or the " House" into 

 the ultimate coordinated agencies within, molecular complexes, which 

 are responsible for the inception and continuing of all the activities. 

 There are cells, it is true, of many kinds and different degrees of struc- 

 ture and organization, accordingly a more elemental unit must be 

 sought which is essential to establish harmony or unity in life's ultimate 

 phenomena or reactions. Vaughan, who is the last of the above to write 

 from his own investigations, says: "The cell is not the unit of life; life 

 is molecular. Life is function, not form." Again he says: "Cells 

 consist of a chemical unity made of giant molecules." Moore states 

 that "the unit of the biologists is the living cell," but he himself 

 approaches it from the standpoint of molecular structure. He would 

 impugn the attitude and circumscribe the field of the biologist by the 

 limits of morphology whereas, in fact, the biologist interprets organic 

 life by means of the various ultimate elements included so far as this is 

 possible and endeavors to unify all forces and structures in an inti- 

 mate unity. 



Physiology in taking cognizance of the cell itself and its environment 

 is reduced to its simplest and lowest terms in the cell possessing an 

 individual entity, for a large part of this physiology is found represented 

 in its most rudimentary and elemental forms and consequently quite 

 easily studied. 



Nutrition as it is illustrated in B. subtilis is easily approached as 

 compared with that of man. It is not difficult to reproduce, change, 

 and control nutritional conditions in a unicellular organism as compared 

 with the multicellular organisms. Methods which enable the investi- 

 gator to reproduce, manipulate and supervise microorganisms enable 

 him to attack problems excluded from the category of the multicellular 

 physiologist. However, the physiologist of complex forms, as the 

 human, not only has his problems rendered more intricate by the organ- 

 isms he studies but he also has them multiplied because of the many fold 

 combinations of cells. Bayliss is substantially correct when he says, 



