1912'] Malarial Pigment in Malarial Paroxysm 99 



an alkaline hematin solution and the suspended pigment readily 

 passes through Schleicher and Schiill filter paper No. 597 

 which has been used as the routine filter. With different prep- 

 arations of hematin these variations in solubility are contin- 

 ually appearing. Reference is made to this feature of the 

 hematin solution to indicate the difficulty in maintaining abso- 

 lutely uniform experimental conditions and accurate dosage. 



Experimental Procedure. — Briefly, the experiments have 

 been conducted according to the following plan: The animals 

 were accustomed to laboratory surroundings by being kept in 

 cages from one to two days before any observations were made. 

 The normal temperature curve of each animal was then estab- 

 lished by rectal temperature, taken every half hour from 8 or 

 9 A. M. until 3 or 4 p. m., the time to be covered by subsequent 

 experiments. As it seemed probable that the sodium bicar- 

 bonate salt solution used as the solvent for hematin might pro- 

 duce some toxic manifestations when injected intravenously, 

 the action of this solution was determined in a number of in- 

 stances, usually in such doses as were subsequently to be admin- 

 istered with the hematin. While these control tests were 

 usually made prior to the injection of hematin, some such tests 

 followed the administration of hematin. The animals were 

 next given intravenous injections of alkaline hematin at 8 or 

 9 A. M.^ and the resulting phenomena were noted, the tempera- 

 ture being taken as previously, although fifteen-minute obser- 

 vations were frequently made. 



Dose of Hematin. — It is evident that the question of dosage 

 in such a series of experiments is one of prime importance. To 

 carry out the object of these experiments it is quite essential 

 that the dose of hematin employed be somewhat comparable 

 to that liberated into the human circulation at the time of seg- 

 mentation of a generation of parasites. While there is no evi- 

 dence to show that all the hemoglobin of the infected red cor- 

 puscles is decomposed to form hematin, if we may assume 

 that such is the case, and, further, that a 1 to 5 per cent, 

 infection of red blood corpuscles is not uncommon, we have 

 suflacient data upon which to base a calculation of the approx- 



