400 



RESEARCH IN PROTOZOOLOGY 



^ 1 



whether or not an infection is simple or multiple, for where there 

 is more than one brood of parasites, the percentage of very small 

 forms will never reach the high percentage attained in single infec- 

 tions, such as is shown in Fig. 27. 



Mean Size o 



Coefficient of \&riation o 



lirasite Ratio • 



1 



RM. ' A.M. RM. ' AM. PM. ' A.M. 



5 b 7 



Day of InFection 



RM. ' A.M. RM. ' A.M. 



RM. ' AM. RK AA 



Fig. 26. — Graph showing the changes in mean size, variability in size and 

 number counts (ratio of parasites per 10,000 red blood cells) for the asexual 

 forms through the acute and beginning of chronic periods in Bird 61. The 

 arrows indicate the time of maximum sporulation. (From L. G. Taliaferro, 

 1925.) 



Some additional data will indicate the extent of the synchronicity 

 and consist in ascertaining the coefihcient of variation for size of 

 the parasites from the data already obtained. Briefly, the coefficient 

 of variation may be found as follows : 



I. The standard deviation is calculated from the measurements 



already obtained by the formula 



V 



Ix' 



M^, in which I!x^ repre- 



sents the sum of the squares of the individual measurements them- 



