106 Journal of the Mitchell Society [^December 



hematin, the rabbit usually manifests a slight degree of rest- 

 lessness, then crouches in a corner of the cage. In the second 

 stage of the paroxysm the vessels of the ears contract giving to 

 the shaved ears a pale and cyanotic hue, while at the same time 

 the ears become decidedly cold. In pronounced cases the surface 

 temperature (temperature of the ears) may be more than 30° 

 F. below the rectal temperature. The lowest temperature re- 

 corded in this series of experiments was 63.5° F. with 

 a room temperature of 62.5° F., and a rectal temperature 

 of 105° F. During this stage the animal's ears usually 

 lie on its back, and the hair tends to become erect, pre- 

 senting the picture of an animal that is cold. Meanwhile, the 

 rabbit shows convulsive tremors or shivering, but rarely any 

 continued or pronounced shaking. This stage of chill lasts 

 from forty-five minutes to one hour, and is terminated rather 

 abruptly by a dilation of the superficial vessels, the ears rapidly 

 becoming flushed and hot. The animal now moves about the 

 cage or stretches out and remains quiet. Further than this, 

 the third or hot stage of the paroxysm possesses no especial 

 symptoms and its limit can be fixed only by the course of the 

 temperature, which may remain well above normal for several 

 hours, or sink to normal within an hour. During the third 

 stage and the latter part of the second stage of the paroxysm 

 the animal shows a pronounced thirst which is undoubtedly 

 referable to the febrile condition. 



The most striking and at the same time the most constant 

 of all these symptoms are the contraction and dilatation of the 

 superficial vessels associated with the corresponding lowering 

 and elevation of the surface temperature. 



The contrast between the symptoms of the animal injected 

 with hematin and those of control animals is quite as sharp as 

 in the instance of the temperatures. With doses of hematin 

 sufiiciently large to produce pronounced symptoms of the type 

 described, corresponding doses of sodium bicarbonate salt solu- 

 tion produce practically no recognizable effect. There may be 

 a suggestive or very transient change in the surface vessels and 

 the temperature, but nothing that is definite or constant. When, 



