316 Mr. G. H. K. Thwaites on a peculiar state of the Palmellese. 



duly consider this fact, how much does it exalt the lower tribes of 

 plants in our estimation ! since we may contemplate an individual 

 plant of them not as the single phyton — not as the single frond — 

 not as the single cell — but as the aggregate of, it may be many 

 thousands of, these ; — view it occupying as much space and ex- 

 ercising as great an influence in the oeconomy of nature as the 

 largest forest tree j and as rivalling this even in longevity. It 

 must be remembered that in the tree the manifestation of vitality 

 is entirely in the recently formed leaf-buds in progress of deve- 

 lopment. 



Under the influence of preconceived opinions it is difficult at 

 first to take the view of the subject now off'ered, and it seems 

 easier to view each leaf-bud of the tree, rather than the tree itself, 

 as a distinct individual plant, comparing the former with the 

 phyton of the lower plant. We must, however, go further than 

 this : — the gemmse of the Palmella are analogous^ it is true, 

 to the leaf-buds of the higher plant, but they are homologous, 

 which is of higher importance with reference to this question, to 

 the individual cells of the higher plant. To be consistent, there- 

 fore, we should be driven to the necessity of regarding the higher 

 plant as made up of as many individual plants as there may be 

 cells in its tissues. Now there can surely be few physiologists 

 who would be disposed to adopt such an opinion ; notwithstand- 

 ing it cannot be denied that each of such cells possesses a greater 

 or less independent vitality of its own. The application too of 

 such a doctrine to the animal kingdom would appear to be im- 

 possible. 



To some it may appear of little importance whether any parti- 

 cular vegetable organism is to be regarded as a complete indivi- 

 dual plant, or as merely a part or subdivision of such, — whether 

 it is the entire product of a true impregnation or a portion of 

 it ; but to the physiologist the general question is one of very 

 great interest, since the solution of it enables him to compare 

 correctly the higher with the lower forms of vegetation, and to 

 understand what may previously have appeared anomalies in the 

 vegetable kingdom. 



EXPLANATION OF PLATE X. 



Fig. 1. Portion of mass o^ Palmella hotryoides, Grev,, in an early stage of 

 development, showing the cells attached to the tubular filaments. 

 — 2. Cells of the same species, when in a more advanced stage of growth, 

 each seated at the end of a mucous prolongation. 

 All highly magnified. 



