396 



Alfred J. Eivavt 



Generally summarising the means of the foregoing results, the 

 substances tested may be grouped in the following order as 

 regards their toxicity to adult apples. Mercuric chloride, copper 

 sulphate, lead nitrate, gold chloride, zinc sulphate, sulphuric 

 acid, the sulphates and nitrates of brucine, strychnine, atropine 

 and morphine, nitric acid, barium chlorate, magnesium sul- 

 phate, citric acid, oxalic acid, chloroform, potassium chlorate, 

 formaldehyde, ammonia, calcium hydrate. It follows also from 

 the table that the poisonous action of the mercuric, cupric, lead 

 and gold salts is due almost solely to their basic components. The 

 comparison between barium and potassium chlorate shows that 

 barium as a base is distinctly poisonous to apples, whereas the 

 poisonous action of magnesium sulphate is largely due to its 

 dissociated sulphate ions. To a lesser extent the same is 

 true for the salts of alkaloids, but the bases in this case do 

 appear to have themselves an inherent and fairly pronounced 

 poisonous action. Strychnine was much more poisonous to Rome 

 Beauties than the other alkaloids. The relatively feeble poison- 

 ous action of oxalic acid as compared with sulphuric acid may be 

 partly due to the lesser dissociation of its hydrogen ions, and 



