XVIU INTRODUCTION 



in their membranes, the inhibition of the formation of which could lead 

 to a suppression of growth. In view of the past history of science, anyone 

 is presumptuous to claim they can distinguish what is important from what 

 is not — we have to do this much of the time, of course, but we should 

 realize we are presumptuous. There are probably some errors in the tables, 

 since it is often difficult to determine exactly the conditions used; one is 

 sometimes referred to a previous report, but cannot be certain that all the 

 conditions have been maintained throughout the work. One must often 

 guess a parameter from other work the investigators have done, and some- 

 times calculate results from heterogeneous data. There has been a good 

 deal of calculation, and recalculation, and averaging, and I take full re- 

 sponsibility for anything right or wrong I may have done. A number of 

 curves have been replotted or data represented in a way that differs from 

 that of the original investigator, and I fully realize that this usuallj' results 

 in nothing but animosity. 



