94 



A. P. Mathews 



action of salts on fish eggs/ the diastatic ferment,^ bromelin,^ a pro- 

 teolytic ferment, and growing tips of peas and beans/ Table 3 shows 

 that the chlorides of the various metals arrange themselves, as regards 

 their toxicity, with few exceptions, in the order of the potential energy 

 of their ions. Ions of low potential energy, such as those of sodium, 

 lithium, magnesium, and potassium, being relatively inert, when com- 

 pared with the enormously toxic action of the ions of high potential 

 energy, such as nickel, lead, hydrogen, ferric, cupric, mercury, silver, 

 gold, and platinum. 



There is, I think, no mistaking this general parallelism, which was 

 theoretically anticipated. By no other properties known to us can 

 the metals be arranged in an order so closely corresponding to their 



TABLE 3. 



Minimum Fatal Doses of Salts for Various Ferments and Organisms. 



(F = Dilution Minimum Fatal Dose (Equivalent).) 



SALT 



Ag NO3 



HgN04 



Hg Ch 



Hg(CN), 



Cu SO4 



Cu Cla 



TeCla 



Pb (N03)> 



Pb Ch 



Pb (CHjO,),.. 



HCl 



Cd (NO3), 



CdCU 



Ni CI, 



NiSO^ 



CoCh 



Co SO4 



Co (NOj), 



Fed, 



FeSO* 



Zn Cl 



Zn (NO,), 



Zn SO4 



Mn Ch 



AICI3 



MgCU 



Mg (NO3), 



Li Cl 



CaCl... 

 Ba CU.. 

 Li Cl,... 

 NaCI... 

 KCl.... 

 Na NO3. 

 KNO3.. 



Minimum Fatal Dose (V) Equivalent Dilution 



Diastase 



< 100,000 

 30,000 



8,333 

 333 

 3o(?) 



990 



142 

 910 



69 



6.25 



3-3 



I 



1-4 



4 



1. 1 



2-5 



> 3 



> 3 



Roots of 

 Lupinus 



300,000 



51,200 

 12,800 

 12,800 



6,700 



3,200 

 51,200 



12,800 



12,800 

 12,800 



6,400 



'Authors' results. 

 ' McGiugan, luc. cit. 



3 CaldweU. 



* Kahlenberg and True, loc. cit.; rieald, loc. cu 



