14 



Livingston : Chemical stimulation of a green alga 



not entirely to be attributed to the cation. This would agree with 

 the results of certain other authors to be cited later. {Fig- ^4- 

 shows palmella and dead cells from 3;^/ioo,ooo.) 



{ ferric) (FeiNO 



The cells are all killed 



at ;//i 0,000. They live as the palmella form in concentrations of 



5^/ 



At 7/// 



?/ 1 00,000 and ;// 



000 the growth is normal for weak solutions. For these tests 

 iron was omitted from the nutrient medium to which the poison 

 was added. 



/j. Lead nitrate (Pb(N03)2). — Death ensuses in nj 10,000. 

 In 5«/ioo,ooo, the majority of the cells die, but some become of 



15 



Figure 14. Palmella and several dead cells from 3/7/100,030 H^SO^. 

 Figure 15. Palmella from w/i, 000,000 AgNO^. 



the palmella form. The latter form is maintained through the 

 series to 5///1, 000,000, in which solution there are usuallv a num- 



lents, although most of the culture is of spherica 

 acceleration occurs in ;//ioo,ooo to 5«/i, 000,000 

 to 572/10^000,000, the growth of filaments anc 



cells. Zoospore 

 In nj 1,000,000 

 zoospores is the same as in the control. 

 16. Lithium nitrate (LiNO,). — Many 



die in ^nl 



palmell 



5^/ 



