THE LIFE-HISTORY OF THE LEUCOCYTE 265 



having three segments ; Class IV with quadripartite nucleus, 

 having four segments ; and Class V with multipartite nucleus, 

 having five or more segments. 



In health and under normal conditions, segmental neutro- 

 phile blood picture is remarkably constant, giving very little 

 variation from the numbers given by Arneth, as shown in 

 Table I, which constitutes the normal : 



Table I. — Showing Normal Arneth's Count 



Number of segments in percentages 



Class I. 



II. 



III. 



35 



41 



IV. 



17 



In pathological conditions, on the other hand, especially 

 when associated with toxaemia, this relationship is altered, 

 the amount of alteration being proportional to the toxsemia 

 present. This alteration consists in a diminution of the more 

 segmented forms, so that a relative increase of Classes I and II 

 results. This condition Arneth speaks of as " laevodeviation," 

 or " dislocation to the left." This laevodeviation in various 

 diseases is readily seen in Table 11. 



Table II. — Showing Laevodeviation in Various Diseases 



It is in connection with pulmonary tuberculosis that I have 

 specially observed this condition. In a series of cases of 

 pulmonary tuberculosis in which, in collaboration with Dr. 

 Horace Wilson, I have investigated the condition of the leuco- 

 cytes after Arneth's method, very interesting results were 

 obtained. t^' 



In one series where phthisis was merely suspected, the 

 counts were normal, showing no deviation, and none of these 

 patients developed the disease. In another series, where the 

 patients all died at no very distant date after making the 



