the isotonic point of the blood of a patient suffering 
from chronic malaria, and who had had no blackwater 
for a month, and found it to be 0*44 per cent. NaCl, 
i.e., its resistance was less than normal. 
(b) One hour after taking quinine, at the 
beginning of the actual haemoglobinuria, the 
resistance had fallen, i.e., the isotonic point had gone 
up to 0*46 per cent. 
{c) Four hours after the haemoglobinuria, the 
resistance had increased up to 0*41 to 0*42 per cent. 
(d) Nine days after the haemoglobinuria it had 
reached the normal. 
Haemolytic Action of Quinine .—(1) The amount 
of quinine hydrochloride (neutral) sufficient to haemo- 
lyse 1 c.c. of an emulsion of washed red cells at 37 0 C., 
in vitro , was o*ooi to 0*00082 gramme in a healthy 
patient. (2) On the contrary, in the blackwater 
patient, it was less, viz. : 0*0008 to 0*00062, or even 
during an attack, 0*0005. 
Action of Calcium Chloride. —The blood in the 
above case, with an isotonic point of 0*46, was exposed 
to the action of calcium chloride (one drop of a ten 
per cent, solution, to 3 c.c. of the blood cell emulsion). 
The corpuscles were then washed in 0*075 per cent, 
salt solution once. The isotonic point was now 
found to be lower, viz. : 0*41, i.e ., the resistance to 
haemolytic agents was raised. 
6. Count the red and white cells. The red cells 
are, as a rule, quite normal in shape. 
7. Determine the amount of haemoglobin. 
8. Make films every two hours if possible {as 
early as possible ), noting accurately the time and 
temperature at which the films are made. 
9. Examine films for parasites ; if these are 
absent, search carefully several large films for pigmented 
