22 



CLINICAL OBSERVATIONS 



In 59 cases Dr. Monroe A. Mclver examined blood smears 

 stained by Giemsa. Special attention was given to the forms of 

 leucocytes and differential counts were made. He studied 

 particularly the relative proportion of neutrophiles with no 

 division of the nucleus to those with two or more divisions con- 

 nected only by threads. This investigation was done because it 

 had been reported that in typhus fever an abnormal number of 

 the neutrophiles have undivided nuclei, and that this observa- 

 tion had diagnostic value. 



A composite differential count constructed by averaging the 

 totals of these 59 counts, all taken in the second week of the 



TABLE II 



disease, is as follows: Lymphocytes, 18.6 per cent; large 

 mononuclear basophiles, 5.9 per cent; neutrophiles, 75.4 per 

 cent; (neutrophiles with incompletely divided nuclei, 50.7 per 

 cent; neutrophiles with two or more distinct divisions of the 

 nucleus, 24.7 per cent). In two cases two cells were seen in the 

 course of the count in each which had all appearances of myelo- 

 cytes. Eosinophiles were completely absent in all smears, as is 

 known to be characteristic of typhus fever. Blood platelets 

 were apparently normal in number but seemed to be of un- 

 usually large size. The red cells were of normal appearance. 



Finger blood from 169 patients was examined, usually once 

 only, for rickettsia. The blood was taken at all periods of the 

 disease, usually within the first ten days. Thin and thick 



