Size as Structure and Function 7 



2. These values mean that the measurement of an in- 

 dividual Bacillus coli on the tenth day of culture rep- 

 resents nine times the amount of solid matter that it 

 represents on the second day of culture. 



In general, the size as measured represents very 

 closely the absolute amount of water incorporated in 



2 4 6 8 10 12 



Time after implantation in days 



Figure 2. Progression in percentage water content of Bacillus coli with 

 age of culture, on an agar medium at 37°C. (Data of A. I. Dawson, '19). 



the individual, but only very approximately the 

 amount of any other chemical entity. Structurally we 

 cannot tell the difference between an organism which 

 is nearly all water and one which is in large propor- 

 tion other substances. In any case the substance 

 measured can only be obscurely termed "protoplasm." 



