Cuar. Il. THE PROCESS OF AGGREGATION. 68 
carbonate of potash to 218 of water, and no decided change 
could be perceived in the cells of the roots; but when these 
same roots were placed for 25 m. in a solution of carbonate of 
ammonia of the same strength, little green spheres were formed. 
A green marine alga was left for some time in this same solu- 
tion, but was very doubtfully affected. On the other hand, a 
red marine alga, with finely pinnated fronds, was strongly 
affected. The contents of the cells aggregated themselves into 
broken rings, still of a red colour, which very slowly and 
slightly changed their shapes, and the central spaces within 
these rings became cloudy with red granular matter. The 
facts here given (whether they are new, I know not) indicate 
that interesting results would perhaps be gained by observing 
the action of various saline solutions and other fluids on the 
roots of plants. 
