SALT EFFECTS IN BACTERIAL GROWTH 



585 



culture at the lircaking point of the growth curve is approximately 

 the same in all cases. It also appears that the salts have the 

 effect of shortening the latent period previous to rapid growth. 

 This difference is marked in the case of the sulphate (0.1 M), 

 which appears to have a somewhat greater accelerating effect 

 than the chloride, while in the case of the NaCl (0.2 M) the 

 shortening effect upon the period of lag is not so definite; or may 



pcfiurr Q--J.0 in.r' 'Ne.C.y 



7 o } . /o // 

 Days at ia.'C. 



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be entirely lacking, as is indicated by the results of experi- 

 ment 2. 



The effect of NaCl upon the period of lag was therefore ex- 

 tended in experiments 3 to 6 in which plate counts were made 

 at hourly intervals. The results of these additional experiments 

 again show that while NaCl may or may not decrease the latent 

 period, it increases in every case the velocity of growth during 

 the period of active multiplication. 



It was thought that it might be possible to magnify the effect 

 of NaCl by incubation at a temperature which allowed only a 



THE JOURNAL OF BACTERIOLOOY, VOL. VII, NO. I 



