432 



G. S. WILSON 



centimeter, when the Helbe chamber can be used, there appears 

 to be no method of insuring accuracy in the results. As varia- 

 tions of 50 per cent and more were encountered by the Thoma- 

 Zeiss method it was decided to abandon this altogether and wait 

 till the numbers were sufficiently great to allow the Helbe to be 

 used. In future experiments, then, no record of the total counts 



LOG. or 



COUNT 



8-0 



CX PT. 1. 



ti 



To 



fei 



6o 



S-S 



5-0 



-T- 

 5O0 300 400 



Time in minutes, 



T- 



500 



Fig. 4 Showing the Total axd Viable Cotjxts in a Broth Culture of 



Bact. suipestifer 

 Total count = continuous line. Viable count = interrupted line 



during the early phases was made. There is no doubt that this 

 is a grave disadvantage, for it prevents one from obtaining figures 

 by which to compare the total and viable counts in the early 

 stages of the logarithmic phase. In practice it was only found 

 possible to obtain one to three comparative counts before the 

 close of the logarithmic phase. As, however, the organisms are 

 dividing more or less uniformly during this phase, it is fair to 

 assume that the relation between the two during the whole of the 

 phase is fairly closely represented by that obtaining during the 



