THE LIFE-HISTORY OF THE LEUCOCYTE 267 



cells, and that the measure of their functional activity may be 

 obtained by ascertaining the phagocytic power of the various 

 classes of leucocyte when placed in the same environment and 

 subjected to the same dosage of opsonin. 



In a series of 42 opsonic index determinations for the 

 Staphylococcus pyogenes aureus, in which 4,183 polymorpho- 

 nuclear leucocytes and 6,340 micro-organisms were enumerated, 

 I have taken the phagocytic activity of the leucocytes as an 

 index of their functional activity, the results being shown in 

 the accompanying table (Table IV), and graphically in the 

 accompanying chart (Chart I). 



Table IV. — Number of Leucocytes and Ingested Cocci in 42 Opsonic Index 



Determinations 



The table and chart (Chart I) clearly show that the neutro- 

 phil leucocyte of Class I with undivided nucleus possesses a 

 moderate power of phagocytosis (1-39), that this power of 

 phagocytosis reaches its maximum in leucocytes with bipartite 

 nucleus in Class II (1-62), and then progressively diminishes 



Leucocytes 



1"7 



1:6 



1-5 

 V4 

 1-3 



1-2 



Chart i. — Showing average number of cocci ingested by leucocytes according to 



number of nuclear segments. 



The decimal fig^ires given on each side of the chart indicate the number of cocci injected 



per leucocyte. 



through Class III (1*51) and Class IV (1-47) as nuclear division 

 increases, being lowest in Class V (1-35). 



Again, in cases where tuberculin was administered, it was 

 observed that those showing laevodeviation lived longer than 

 those with similar counts where tuberculin had not been 

 administered. This observation would appear to suggest that 

 the administration of tuberculin counteracts to some extent 

 the effects of the toxaemia present. 



The analysis of the cases investigated by this method thus 



