WHAT IS A PLANT ? 75 



Among the higher forms on either side, no difficulty of any 

 moment presents itself. We do not confuse the antelope with the 

 herbage on which it browses, nor the tiny humming-bird with the 

 foliage under which it loves to nestle. The points of agreement 

 between the bride and the orange-blossom are not numerous. 

 They all possess what we call " life," but in form, power of motion, 

 and sensation, and other characters, we seem to find differences 

 wide enough to enable us to assign to each its proper position with 

 absolute certainty. 



Now, go much lower down the scale in both kingdoms, and we 

 are beset with difficulties on all sides. The arduous nature of our 

 task begins to assert itself. Enter the newly-found world of the 

 microscopist, where the width of an eye-lash is an almost gigantic 

 measurement, and we are face to face with perplexities that baffle 

 the efforts of even our most earnest and patient searchers after 

 truth. Many of these lowest forms, such as the Protozoa, are 

 certainly animals ; many, such as the Protophyta, are indubitably 

 plants. Thus, our definition, to be comprehensive and logical, 

 must needs embrace all these forms ; therefore, we must investi- 

 gate them, and learn their life-history. Here it is that our greatest 

 difficulties meet us ; here it is that we find our work is hard and 

 laborious. 



Our older naturalists found similar perplexity in the case of 

 the Sponges, which, after being bufi'eted about unceremoniously 

 from one kingdom to the other, finally found rest on the animal 

 side. The red corals were only some 170 years ago first assigned 

 to the zoologist, who still holds claim over them. Over Volvox 

 globator there waged many fierce battles, until the botanist once 

 and for ever gained the victory. Of such cases as these the poet 

 Crabbe wrote : — 



" Involved in sea-wrack, here you find a race 

 Which Science, doubting, knows not where to place." 



Professor Haeckel proposes the formation of a third kingdom, 

 which he calls the ^''Regiiuni Frofistiaim,'^ for the reception of those 

 doubtful organisms which cannot be absolutely assigned to either 

 the animal or vegetable side, under the collective title of the 

 '''Protista:' To establish this " refuge for the destitute " is at the 



