108 



Journal of the Mitchell Society \_Decemher 



differences of elevation of temperature on successive days 

 of the two animals receiving ten milligrams per kilo, and in b 

 those receiving fifteen milligrams per kilo. 



Text-fig. 4. Variations in the elevation of the temperature with repeated 

 injections of a given does of hematin. 



While the curve of temperature reaction in each case is 

 extremely irregular, it is in general characterized by a tend- 

 ency towards a decrease, which in the instance of animals 16 

 and 17 persists throughout the experiment. With animals 15 

 and 18, however, a second phase of increased reaction is devel- 

 oped. These animals also exhibited the most marked sympto- 

 matic effects throughout the experiment. If the temperature 

 curve alone be considered, it is certain that the tendency is 

 toward a decreasing response to successive injections of hem- 

 atin, and this I have found to be true in other experiments. If 

 we take into consideration other evidence of intoxication, 

 however, as in animals 15 and 18, this decrease seems referable 

 not so much to a tolerance as to over-intoxication. Again, as 

 these symptoms of intoxication decrease and the fluctuations 

 of temperature increase correspondingly, there may be devel- 

 oped a certain degree of tolerance. On the other hand, as 

 shown in animals 16 and 17, there may be an increasing resist- 

 ance to the hematin from the start as the toxic symptoms as 

 well as the temperature decrease proportionally. 



