[Vol. 10 

 264 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



50-cc. volumetric flask. This procedure insured the uniformity 

 of the culture solution in the various flasks. All cultures were 

 incubated at 25° C. 



For each experiment, with a single fungus enough flasks of 

 solution were made up for 2 cultures to be used for each set of 

 determinations. These determinations were made at first on each 

 flask and the results averaged. Later the contents of the 2 flasks 

 were mixed together and the analysis on the mixed solution taken 

 as the average. The fungous mat was filtered off on a weighed 

 and folded filter and washed with distilled water, the filtrate 

 and washings being collected in a clean 200-cc. volumetric flask. 

 The flask was then made up to the mark with distilled water and 

 mixed. Where the mat was sufficiently coherent it was washed 

 as much as possible in the flask before removal to the filter. The 

 titer, P H , reducing sugar, and total carbon were determined, and 

 where time was available other tests were carried out. The 

 determinations were started on the first day that appreciable 

 growth was visible and followed up at intervals calculated to give 

 a number of points on the curve where change was rapid and 

 fewer where the change was slower. 



Where a large amount of routine work is to be carried out, long 

 tedious processes of analyses must be eliminated in favor of shorter 

 and simpler procedures even at the expense of absolute accuracy. 

 Moreover, in dealing with the growth of organisms the variations 

 are likely to be so great as to nullify the accuracy of any single 

 determination. In interpreting the results, likewise, it is far more 

 desirable to have a considerable number of results indicating a 

 continued difference than to have a single result indicating a 

 single difference. No matter how accurate the latter might be, 

 the variations are sufficient to make it no better than an even 

 chance that the single result represents a variation from the nor- 

 mal condition. These considerations were kept in mind in inter- 

 preting the results of the experimental work, and conclusions 

 have been drawn only from clear, consistent differences. 



In plotting the curves the loss of carbonaceous matter from the 

 solution was plotted rather than the experimental figures, that is, 

 the successive determinations were subtracted from the blank, 

 giving differences or losses, and these losses were plotted. These 



