220 
followed again by a marked leucopenia which is at its 
maximum before the onset of the next attack. 
wc 
RC 
instead of 
may be 
500 ' 800 
Billet (Fig. 71), who has traced out hourly the 
relation of the leucocyte curve to the temperature 
curve, has shewn that in regular curves of the tertian 
or quartan type, the leucocytic curve follows closely 
the variations in the temperature. Thus, before the 
febrile attack in a quartan, there may be a leucopenia 
represented by 0 ^ = —— ; at the time of the attack, 
RC 
1200 
however, there is a leucocytosis of 
WC 
RC 
1 
200 
This gradually disappears, passing through the 
normal value ■ 1 ^ , and again reaching a marked leuco¬ 
penia before the next attack. The variations are of 
the same kind in irregular temperatures, the leucocy¬ 
tosis corresponding to the rise of temperature, and the 
leucopenia to the apyretic intervals. 
The Percentage Value of the Leucocytes. —If we 
now make a differential count in a stained specimen 
we shall be able to ascertain what change, if any, there 
is in the relative percentage of the different kinds. 
1. The main characteristic change is that there 
is an increase in the percentage of large mononuclears, 
so that at times they may even outnumber the poly¬ 
nuclear. 
2. The change is especially well-marked in the 
periods of apyrexia (i.e., when there is a leucopenia). 
When there is a leucocytosis the increase in the mono¬ 
nuclears may not be apparent. 
