§2] ACCLIMATIZATION TO CHEMICAL AGENTS 27 



Amoeba, Actinophrys, and various Infusoria are killed by a 

 0.1% solution in a few minutes, and leucocytes and eggs of 

 Echinoids are paralyzed even by a 0.006% solution. Its action 

 is thus more powerful than that of strychnin. The proto- 

 plasm at first contracts, then gradually dissolves and streams 

 away. Upon the higher animals, quinine so acts as to paralyze 

 the central nervous tissue (in MoUusca, Kktjkenberg, '80, 

 p. 10), and it affects the cerebrum and heart ganglia of 

 mammals. 



Antipyrin, or phenyldimethylpyrazolon, is an alkaloid de- 

 rived from and belonging clearly to the benzol type, in which 

 one atom of H is replaced by a complex atom-group, as may be 

 seen from the formula — 



/CH\ HC C - CHs 



I I 0C\ /N-CH3 



HCv ,G ^N^ 



The effect of this agent upon Protozoa has been studied by 

 ScHtJKMAYER ('90, pp. 434-437) and Massaet ('93, p. 64). 

 A solution of 0.1% acting for 80 minutes, caused Oxytricha 

 at first to move more rapidly, but eventually to become 

 transformed into a shapeless mass, whose protoplasm disinte- 

 grates. Acting upon Noctiluca, a 0.25% solution causes a 

 bright glimmer immediatelj' after applying, followed by dark- 

 ness again. Thus there is here a momentary hyperesthesia. 



§ 2. Acclimatization to Chemical Agents 



It is clear that the protoplasm of different organisms is dis- 

 similar. We see this in the different reactions to the same 

 chemical agent. Not only is the reaction of the various spe- 

 cies unlike, but individuals of the same species from different 

 localities differ widely. (Cf. LoEW, '85.) 



We are, naturally, most familiar with this phenomenon in 

 the case of man. Thus, the common North American poison 

 ivy (Rhus toxicodendron) produces, in some persons, extensive 

 inflammation in parts which have come even indirectly in con- 



