drug has of inducing attacks of haemoglobinuria 
(blackwater fever) in patients resident in regions where 
malaria is especially virulent, and where generally the 
parasite form is the malignant tertian associated with 
an extremely high endemic index of native (children) 
malaria. 
Two hundred c.c. of urine are acidified with 
some drops of sulphuric acid. A spoonful of solid 
picric acid is then added. The solution is allowed to 
stand for an hour and then filtered. The solution 
should be quite clear and should give with a saturated 
solution of picric acid no turbidity. If there is 
difficulty in getting a clear filtrate add a trace of egg 
albumen and filter again. The half-dry residue is 
then digested in an* Erlenmeyer flask with fifty c.c. of 
3*o per cent, soda solution for half an hour on the 
water bath. Now add sixty c.c. chloroform ; shake 
for two hours in a shaking apparatus. The solution of 
chloroform is now removed by means of a separating 
funnel and collected in a weighed flask. The flask 
should have a long neck to prevent spurting. Evapor¬ 
ate in a water bath and dry at I20°C. The residue 
is quinine. The experimental error is only one to 
two per cent. 
Determination of the Periodicity of 
Parasite Development 
The inspection of a temperature chart is not in 
itself sufficient to determine the cycle of development 
of a parasite. Thus, as is well known, a quotidian 
temperature chart may be produced by a double 
tertian (simple) or by a triple quartan infection. If 
then, in the case of the double tertian, we made micro¬ 
scopical examinations at definite intervals for forty- 
