30 



Livingston : Chemical stimulation of a green alga 



Fatal strength 



AsJ'ergilhis'i. 



C0SO4 



HCl 

 CuSO^ 



CUNO3 



H2SO4 

 HNO3 

 Cd ( N'03 ) 2 



AgNOj 



PenicilUun^, 



NH^NOj 



MgSO, 



HCl 



CuSO^ 

 Cu(N03), 



Peniciiltumd 



Protococctis^ 



CoSO^ 

 CuSO^ 

 Cu(N03), 

 ZnSO^ 



HCl 

 H,SO, 



Ni(N03)2 

 HNO 



HgCl, 



ZnSO^ 

 CoSO^ 



LiNO. 



3 



Cd(N03), 

 AgN03 



NH^NOj 



CuSO^ 

 CuCNOs)^ 



Macros/or iU7fi^ , 



HCl 

 H^SO^ 

 Cu(N03), 

 CuSO^ 



Uromyces'. 



NH^NOa 



HCl 



H^SO, 



CuSO^ 

 Cu(N03), 



Sterignta tocystis^. 



CoSO^ 

 ZnSO. 



HCl 

 ' HNO 



3 



NilNOj)^ 

 Cu(N03), 



CuSO^ 

 H^SOi 

 Cd(N03), 

 AgNOj 



Oedocephahitn^. 



CoSO^ 

 ZnSO^ 



HCl 

 HNO3 



H,SO, 

 Ni(N03), 



CuSO^ 

 CuCNOj), 



Cd{N03)2 

 AgN03 





Botrytisd. 



ZnSO^ 

 CoSO^ 



HCl 

 HNO3 



CuSO^ 

 CuNOa 



H,SO, 



NiCNOg), 

 Cd(NO,), 

 AgNOj 



Stiseocloniuin" 



Ca 



Mg 

 K 



Na 



Sr 



Li 



NH^ 



Ba 



Rb 



Co 



H 

 Zn 



Fe 



Ni 



U 



Al 



Cd 



Pb 



Cu 



Ag 



A comparison of the above lists will make it clear at once that 

 there is only a very general agreement between them. In the 

 present state of our knowledge nothing more need be said. 



The literature of the effect of toxic substances on higher 



a more unsatisfactory state 

 It would be somewhat out 

 of the field of the present paper to go here into detail as to the 

 concentrations which accelerate growth and those which kill 

 higher plants. It is well established that most of the metals, 

 when at the right strength, do accelerate growth of seedling 

 roots, but there Is discrepancy 

 the limits. The same is true of fatal doses. Kahlenber 



plants, although more extensiv^e, is n 

 than that concerning the lower ones. 



amon 



* 



* Kahlenberg, L. & True, R. H. On the toxic action of dissolved salts and 

 their electrolytic dissociation. Bot. Gaz. 22 : 81-124. 1896. 



