256 THE MICROSCOPE. 



which this observer set himself to solve, was, How is the 

 cell originated ? It is not here desirable to go deeply into 

 this most interesting inquiry ; the object proposed is to 

 give a slight sketch of the formative processes of plant 

 life, chiefly in its relation to the earliest, or cell condition. 



Almost every day brings forth a new discovery by 

 which old land-marks established with a view to the separa- 

 tion, arrangement, and classification of the vegetable and 

 animal kingdoms become unsettled ; the lowest forms of 

 life, vegetable and animal, approach so near to each other, 

 that we cannot with certainty always discriminate them, 

 and say where the one ends and the other begins. The 

 boundary assigned to the vegetable kingdom is, perhaps, 

 too limited, and our definition of a vegetable organism 

 requires to be enlarged : of this any one who will be at 

 the trouble to study the microscopic forms of life must 

 feel perfectly convinced. At the present day, the only 

 generally applicable rule that can be applied to distinguish, 

 animals from vegetables is the dependence of the animal 

 for nutriment upon organic compounds already formed, 

 which it takes into the interior of its body; this at 

 once distinguishes it from the plant, which only possesses 

 the power of obtaining its alimentary matter, by absorp- 

 tion, from the inorganic elements by which it is surrounded. 

 Although there appear to be certain exceptions to this 

 rule, yet it almost universally prevails. 



Kiitzing maintains, that every organic being is con- 

 stituted of vegetable and animal elements, and according 

 as the one or the other prevails, the being becomes an 

 animal or a vegetable : in the first stages of the develop- 

 ment of superior beings, and permanently in those of 

 inferior rank, the two elements are equally balanced. " If 

 nature," writes Humboldt, " had endowed us with micro- 

 scopic powers of sight, and if the integuments of plants 

 were transparent, the vegetable kingdom would by no 

 means present that aspect of immobility and repose under 

 which it appears to our senses." And so with regard to 

 the instruments of motion in the higher classes of crea- 

 tion, the muscles of animals very soon disappear as we 

 descend in the scale to the simplest forms of life ; never- 

 theless, we cannot deny animality to those minute crea- 



