74 INFLUENCES AFFECTING THE LEUCOCYTES 



by a high percentage of* polymorphonuclears and a lessened per- 

 centage of the other variel ies. In cases where exudation is present 

 it is pronounced though t lie increase of leucocytes is not a meas- 

 ure of the amount of exudation. It does not run parallel with the 

 lexer, as there may be a marked leucocytosis with little rise of 

 temperature and on the other hand there may be a high fever 

 wit hout leucocytosis. It measures more the relation of the severity 

 of the infection to the resisting power of the individual. Cabot 

 has expressed this well in the following schema: 



(1) Infection mild, resistance good, small leucocytosis, 



(2) Infection less mild, resistance less good, moderate leuco- 

 cytosis, 



(3) Infection severe, resistance good, very marked leucocytosis, 



(4) Infection severe, resistance poor, no leucocytosis. 



It is observed in individuals in naturally acquired infection; 

 but the course is best seen in experimental cases. In an animal 

 inoculated with pyogenic organisms, first, there is a decrease in 

 the number of leucocytes, this diminution affecting mainly the 

 polymorphonuclears though the large mononuclears are also af- 

 fected (Ewing). Usually after one-half hour to two hours, the 

 leucocytes increase, the increase being principally in the poly- 

 morphonuclears which may attain 85-95%; the eosinophils arc 

 diminished or may disappear entirely from the peripheral circula- 

 tion. After reaching a maximum the leucocytes gradually decrease 

 to the normal number and normal proportions of the several varie- 

 ties are reached. The eosins reappear at the time of the crisis of the 

 disease and may reach higher than the normal percentage during 

 convalescence and recovery. 



In cases of severe infection with poor resistance of the animal 

 the initial leucopenia may persist. This is often seen in cases of 

 septicemia naturally acquired. Inoculating rabbits with virulent 

 cultures of Pneumococcus lanceolatus produces a septicemia with 

 a progressive decrease of leucocytes in the blood. Inoculating 

 attenuated cultures of the same organism produces a leucocytosis 

 :ni(l the animal recovers CTchistovitch). The initial decrease is 

 observed sometimes in cases of naturally acquired infection; but 

 this stage is generally not observed by the practitioner, the case 

 having passed beyond this stage of the disease before the patient, 

 comes under the practitioner's care. Absence of leucocytosis is 



