11 



hydrochlorid was altered by various concentrations of other 

 substances, being almost inhibited by aluminujn nitrate, 

 markedly decreased by calcium nitrate, and only slightly 

 lessened by potassium nitrate. Thus, the effectiveness of 

 these salts in reducing the toxicity of quinin hydrochlcrid 

 diminished with the valency of the cation. Similar results 

 were obtained with the same series of salts in combination 

 with methyl violet. The effect of combinations of various 

 substances with piperidin was in most cases markedly to in- 

 crease its toxicity. Szucs apparently considers the antagon- 

 istic action in the cases investigated by him to be due to 

 the lowering of the rate of absorption of the toxic ion by 

 the presence in the solution of another ion of similar sign. 

 He concludes in sucmarizing that:- "Die Ursache der 'antag- 

 onistischen lonenwirkungen* liegt in alien von mir unter- 

 suchten Fallen in der gegenseitigen Beeinf lussung der Auf- 

 nahmegeschwindigkeit zweier im gleichen Sinne geladener 

 lonen." 



From the results obtained in the investigation just 

 considered it is apparent that in some cases at least the toxic 



effect of the heavy metals on an organism can 1^ modified by 

 the addition of the proper concentration of certain salts. 

 True and Gies, and Szucs, working with higher plants, attri- 

 bute this influence of one salt on the effect of another to 

 a simultaneous action of the two salts upon the organism it- 

 self, while Clark, working with fungi, relates the inhibit- 

 ion of the toxic effect of heavy metals in combination to 

 some modification of the salts in the solution. The prop- 



