393] E. E. Free 195 



SYMPTOMS OF POISONING BY CERTAIN ELEMENTS, 

 IN PELARGONIUM AND OTHER PLANTS 



By E. E. FKEE 



In connection with other experiments on the effects of pois- 

 onous elements on plants, qualitative tests have been made 

 of the symptoms of poisoning exhibited by the common cul- 

 tivated geranium (Pelargonium zonale) and by several other 

 plants, under the action of certain poisonous elements. The 

 plants were grown in soil under ordinary greenhouse condi- 

 tions. The poisons were applied by pouring the proper solu- 

 tions on the soil when the latter was sufficiently dry to 

 absorb and retain all of the added solution. Seven elements 

 were applied to Pelargonium in five concentrations each. 

 These were the following. Concentrations are in parts of the 

 poisonous element per million parts of soil by weight. 



Concentrations 

 p. p. m. 



Arsenic, as trioxide (As 2 3 ) 2 to 500 



Boron, as borax (Na^BA) 2 to 500 



Copper, as sulphate (CuS0 4 ) 4 to 1000 



Iron, as ferrous sulphate ( FeS0 4 ) 20 to 5000 



Lead, as nitrate (Pb(N0 3 ) 2 ) 4 to 1000 



Manganese, as sulphate (MnSOJ 8 to .2000 



Zinc, as sulphate (ZnS0 4 ) 8 to 2000 



In addition to these seven elements the following were ap- 

 plied in one concentration only, namely 500 parts per mil- 

 lion: barium, as chloride (BaCl 2 ) ; bromine, as potassium 

 bromide (KBr) ; cobalt, as sulphate (CoSOJ ; chromium, as 

 potassium chromate (K 2 Cr0 4 ) ; iodine, as potassium iodide 

 (KI) ; lithium, as sulphate (Li 2 S0 4 ) ; mercury, as mercuric 

 chloride (HgCl 2 ) ; nickel, as sulphate (MS0 4 ) ; silver, as 

 nitrate (AgN0 3 ) ; uranium, as uranyl nitrate (U0 2 (N0 3 ) 2 ) ; 

 and vanadium', as chloride (VC1 2 ). All of these elements 

 except iron were applied to Impatiens sultani, Coleus blumei 



