226 DROSEBA ROTUNDIFOLIA. CHAP. IX 



changes of form, but after 24 hrs. were motionless; 

 the leaf being flaccid and apparently dead. On the 

 other hand, with leaves subjected for 48 hrs. to a 

 strong solution of the poison of the cobra, the proto- 

 plasmic masses were unusually active, whilst with 

 the higher animals the vibratile cilia and white 

 corpuscles of the blood seem to be quickly paralysed 

 by this substance. 



With the salts of alkalies and earths, the nature of 

 the base, and not that of the acid, determines their 

 physiological action on Drosera, as is likewise the case 

 with animals ; but this rule hardly applies to the salts 

 of quinine and strychnine, for the acetate of quinine 

 causes much more inflection than the sulphate, and 

 both are poisonous, whereas the nitrate of quinine is 

 not poisonous, and induces inflection at a much slower 

 rate than the acetate. The action of the citrate of 

 strychnine is also somewhat different from that of the 

 sulphate. 



Leaves which have been immersed for 24 hrs. in 

 water, and for only 20 m. in diluted alcohol, or in a 

 weak solution of sugar, are afterwards acted on very 

 slowly, or not at all, by the phosphate of ammonia, 

 though they are quickly acted on by the carbonate. 

 Immersion for 20 m. in a solution of gum arabic has 

 no such inhibitory power. The solutions of certain 

 salts and acids affect the leaves, with respect to the 

 subsequent action of the phosphate, exactly like water, 

 whilst others allow the phosphate afterwards to act 

 quickly and energetically. In this latter case, the 

 interstices of the cell-walls may have been blocked up 

 by the molecules of the salts first given in solution, 

 BO that water could not afterwards enter, though the 

 molecules of the phosphate could do so, and those of 

 the carbonate still more easily. 



