fact that the cysts have shown a marked increase in the dried sample. 

 Very decided increases in total numbers are observed in the 70 % and 

 saturated samples, especially the latter. The fall in the bacterial 

 content of the 70 % and saturated samples is not so marked in this 

 instance as it was in the case of the saturated sample in Experiment 11, 

 This is probably due to the fact that the protozoal activity had reached 

 its maximum before the counts were made as is indicated by the increase 

 in the number of cysts. The same cause has probably resulted in an 

 obhteration of any difference, which might have been expected, in the 

 bacterial contents of the 70 % and saturated samples as a result of 

 the difference in the protozoal content of the latter. 



Experiment IV. The 70 % sample, after use in Experiment III, 

 was employed as the starting point in this experiment. The samples 

 to be dried and saturated respectively were taken from it and the 

 remainder was kept for a period of 12 days at 70 % w.H.c. The 

 dried sample was kept for 14 days, the saturated sample for 12 days, 

 and bacterial and protozoal counts were made for all three samples 

 as in the last experiment. The results obtained are given in Table 11 

 Drying has, in this instance, lowered the numbers of protozoa 

 present, while the cysts again remain considerably behind the total 

 numbers. The 70 % sample is, at the end of the experiment, in 

 practically the same condition as it was at the beginning. It is obvious, 

 therefore, that the protozoa in the sample had reached the maximum 

 of their activity during the course of the preceding experiment. Thus, 



