1912'] Malarial Pigment in Malarial Paroxysm 101 



varies widely, even when kept under exactly the same condi- 

 tions. In apparently normal animals I have found the individ- 

 ual extremes between 98° and 103° F. Likewise, the fluctua- 

 tions of temperature in a given animal may be quite consid- 

 erable, but usually follow a fairly definite course. 



The course and fluctuations of temperature of the normal 

 rabbit under experimental conditions, as well as the individual 

 difference in temperatures, are shown in text-figure 1. This 

 chart shows the normal temperatures recorded for rabbits 15, 

 16, 17, and 18. The first three animals were from the same 

 litter, about three-quarters grown, and weighed 1,600 to 1,700 

 grams. Number 18 was full grown and weighed 1,840 grams. 

 All the records were taken at the same time and all conditions 

 were as nearly alike as possible. While three of these curves 

 coincide closely, the fourth shows an extremely low and irreg- 

 ular curve of temperature. It should be noted that the temper- 

 ature in all instances has a downward trend during the morning 

 hours, and does not show an upward tendency until about noon, 

 when there is a gradual rise, which ultimately reaches as high 

 as the temperature at the first observation or even higher. This 

 temperature curve has been fairly constant in my entire series 

 of experiments. 



Effect of Hematin upon Temperature. — If, for purposes of 

 comparison, we adopt the classical division of the malarial par- 

 oxysm into a cold stage, a hot stage, and a stage of sweating, 

 with the concomitant symptoms belonging to each, certain of 

 these manifestations are capable of accurate measurements in 

 an experimental animal, while others may be determined with 

 a fair degree of accuracy by close observations, and still others 

 are wholly indeterminable. Of prime importance among these 

 phenomena of the malarial paroxysm is the question of fever. 



In estimating the temperature effects, in all instances at least 

 three facts are to be taken into consideration: the nature of 

 the effect, the degree of the effect, and the duration of the 

 effect. While it has been possible to assemble much of the data 

 concerning the effects of hematin upon the temperature in an 

 appended table which shows the abbreviated protocols of the 



