72 



MORPHOLOGIC VARIATION 



later phases of growth, the increase in number of cells is much 

 greater than the increase in size of cells, such a curve of total cell 

 length does not differ much from the curve of the number of cells, 

 except during the early hours of growth. In Figure 15 the number 



12 3^5 



Hours. 



Fig. is. Comparison of Growth Curves by Cell Counts and by Total 



Cell Length in the Lag Phase. B. megatherium, Culture I. 



of cells and the total cell length are plotted side by side. It will 

 be seen that the latter curve presents a somewhat shorter latent period 

 and a more gradual acceleration than the former. 



A number of interesting facts are brought out by studying the 

 frequency distribution curves of the cells with regard to their size 



