Leishmania Donovani in Peripheral Blood 219 



validity of this ratio as the governing factor of osmotic activity. 



On the basis of the assumption that the above laws are valid 

 for blood, mathematical expressions have been derived which 

 indicate the distribution of electrolytes and water between cells 

 and serum, and the manner in which the distribution is affected 

 by changes in P H (C0 2 tension) and oxygen content. The effect 

 of varying C0 2 tensions has been investigated, and the results 

 have been found to accord with those calculated on the basis of 

 the above assumption. 



107 (2067) 



Leishmania donovani in the peripheral blood. 

 By CHARLES W. YOUNG and HELEN M. VAN SANT. 



[From the Department of Medicine, Peking Union Medical Col- 

 lege, Peking, China.] 



Donovan 1 who found Leishmania donovani first in the living 

 patient also discovered the parasite in smears from the peripheral 

 blood. Many have advocated the examination stained blood 

 smears for diagnosis of the disease (Patton, 2 Marshall, 3 Can- 

 nata, 4 Knowles 5 ) but all agree that the organism is present in 

 small numbers and that many slides must be carefully studied. 

 Spleen smears obtained by aspiration has been the usual method 

 for diagnosis. As the bleeding time is prolonged in all advanced 

 cases this procedure is not devoid of danger (Donovan, 1 Wylie, 6 

 Knowles, 7 Rogers, 8 Bramachari 9 ). Blood culture has been sug- 

 gested as a substitute but results have been inconstant (Mayer 

 and Werner, 10 Wenyon, 11 Row, 12 Korke, 13 Knowles 5 ). The last 

 named author made 128 cultures from 34 patients with two posi- 



1 Donovan, Lancet, 1904, ii, 744. 



2 Patton, W. S., Indian Jour. Med. Res., 1914, ii, 492. 



3 Marshall, W. E., Fourth Eeport, Wellcome Trop. Res. Labs., Khartoum, 

 1911, 157. 



4 Cannata, S., quoted by Wenyon, Trop. Dis. Bull., 1922, xix, 1. 



5 Knowles, R., Indian Jour. Med. Res., 1920, viii, 162. 



