b DR. NICHOLS ADDRESS. 



wonderful instrument, the uiodein microscope, enable them to give a 

 tolerably satisfactory answer. The nature of the substances employed 

 in building up the plant structure, is well understood, and also the 

 form of mechanism wliich is adopted in the first beginnings of growth, 

 and the chemical changes and transfornjations which occur, but the 

 nature of the cited force which guides, and upon which all activity 

 depends, we do not understand, and it is pi obable human research will 

 nevei" shed much light upon this mysterious, but most interesting 

 problem. The little microscopic cell is tlve workshop in which great 

 chanojes are elaborated, and durino; the season of veoetable o;rowth' 

 this is the seat of the most intense activity. Every plant that grows 

 upon our earth, however great or small, must be considered as having 

 originated from a single cell, so infinitesinially sniall that the highest pow- 

 ers of the microscope are required to observe it. If we turn over one of 

 the pebbles common in our brooks, we shall find a slimy material of a 

 «:reenish hue, adherino; 'to its under side. This coverino;-is a true 

 plant, but it is one of the lowest of known forms. If we examine it 

 with the microscope, it will be found to be perfect in structure, having 

 an organism so wonderful as to command our admiration. Feeble and 

 insignificant as it is, it corresponds in structure with the huge oak 

 which grows by the stream and overshadows it with its branches. The 

 plant that adheres to the rock consists of a single cell, but that cell is 

 as perfect and beautiful as any of those which make up the structure 

 of the oak. The tree is but an aggregation of cells — cells piled upon 

 cells — and the work that is carried on within them is no more complex 

 than that which goes on in the workshop of the humble unicellular 

 plant. 



It is with a choice of terms that we designate the cell as the work- 

 shop of the plant, in which the materials that enter into its organiza- 

 tion are elaborated and fitted to aid in the increase of its substance. 

 The nature of the food which is manipulated within the cell is indeed 

 peculiar, inasmuch as plants gather together the waste products of men 

 and animals, and again fit them for the use of higher organisms. 

 Plant food is oxidized food — food which it is impossible for animals to 

 assimilate — and the plant, in all its functions and in the objects of its 

 growth, manifestly occupies an intermediate position between ourselves 

 and the insensible rocks. This is absolutely essential to the existence 

 of man upon the earth. Of all the functions of plants, the mo.st 

 remarkable are connected with or related to, the solar rays, for they 

 pos.se.ss the power of utilizing the sun's heat ic a way which enables 

 them to pull apart, as it were,' some of the most complex and refractory 

 compounds known to modern chemistry. The most tiny, feeble leaf 

 or blade of gra.ss, has a power in chemical decomposition greater by 

 far than is possessed by Liebig, Bousingault, or any of the great exper- 

 imenters of the age. The separating, in silence, in the quiet of the 

 meadows, by organisms .so frail that we can cru.sh them between the 

 thumb and finger, of a compound so fixed as carl'onic acid, is one of 

 the marvels in nature which puzzles and confounds the ])hilosopher, 

 and leads him to bow in luimilitv before the God of nature, whose 



