326 BACTERIAL POISONS. 



bling cystin. The crystals are soluble in a little water, or 

 on warming, but precipitate again- on cooling. Paraxaii- 

 thine, however, shares with heteroxanthine the property of 

 forming a difficultly soluble compound with the fixed alka- 

 lies, but can be distinguished from the latter by neutralizing 

 with an acid the solution of the sodium or potassium com- 

 pound, when, in the case of paraxanthine, there will be 

 obtained a precipitate of the characteristic crystals of that 

 base ; whereas heteroxanthine is obtaiaed on similar treat- 

 ment as a dense pulverulent precipitate. This reaction is 

 not given by theophylline. 



It is interesting to observe that paraxanthine is isomeric 

 with theobromine, theophylline, and also with a body re- 

 cently described by Fischer as dioxy-dimethyl-purpurine. 

 In its composition it is, therefore, a dimethyl-xanthine. 



The physiological action of paraxanthine has been studied 

 by Saix)mon. Injections into the muscles of 1-2 mg. pro- 

 duced almost at once a rigor-moiiig-like condition of the 

 muscles affected, with diminished reflex excitability without 

 previous increase ; 6—8 mg. introduced into the lymph sac 

 brings on a gradual loss of voluntary motion as well as of 

 reflex excitability ; the rigor is more marked in the anterior 

 extremities, which have a wooden or waxy consistency. 

 Dyspnoea is likewise an early symptom, but as soon as rigor 

 sets in the respirations drop far below the normal, and may 

 even be absent for several minutes. At times the lungs are 

 enormously dilated, same as in theobromine. The heart's 

 action is intact till the very last. In mice tlie reflexes are 

 increased almost to a tetanus. The lethal dose for frogs, 

 subcutaneously, was found to be 0.15-0.2 per cent, of the 

 body- weight — somewhat lower than that of theobromine and 

 xanthine. The action of these three bases is very similar. 

 They produce in common the slow creeping movements, 

 followed by cessation of spontaneous muscle action, com- 

 plete loss of reflex excitability without a previous rise, 

 and the heart's action is not affected till in the latest stages. 



Carnine, CjHjN^Oj, was isolated in 1871 from Amer- 

 ican meat-extract by Weidel, but has not been obtained 



