198 DKOSERA ROTUNDIFOLIA. CIIAP. YIH 



dency ; in these two latter cases the surrounding fluid 

 was not coloured pink, and the leaves were not 

 poisoned. On the other hand, propionic acid, which 

 is poisonous, does not cause much mucus to be 

 secreted, yet the surrounding fluid became slightly 

 pink. Lastly, as in the case of saline solutions, 

 leaves, after being immersed in certain acids, were 

 soon acted on by phosphate of ammonia ; on the 

 other hand, they were not thus affected after immer- 

 sion in certain other acids. To this subject, how- 

 ever, I shall have to recur. 



