PLANT LIFE ON THE FARM. 



It may be a truism to say, that for the process of diffusion 

 the liquids must be diffusible, but the fact must be carefully 

 borne in mind in all questions relating to the feeding of 

 plants. In the case of plants, the phenomenon of diffusion, 

 or the gradual admixture of two liquids of different natures, 

 is complicated by the presence of a membrane in the shape 

 of the cell-wall. The water from the outside has to pass 

 through the membrane to reach the protoplasm on the 

 other side. Speaking broadly, there are no holes in the 

 membrane through which the water can pass. Ingress is 

 secured by that process of diffusion to which reference has 

 just been made, and by virtue of which the molecules of 

 the membrane and the molecules of the water shift and 

 change places ; the space that was occupied by a molecule 

 of membrane is now occupied by a molecule of water, and 

 vice versa* The access, therefore, of water into the interior 

 of a closed cell is the result of the process of diffusion. 

 Where two liquids mix without any intervening mem- 

 brane, the mixture is called diffusion simply ; where there 

 is an intervening membrane, the diffusion process is known 



Protoplasm Cells. The raw material (the term is not 

 quite accurate, but for illustration sake it may pass) is 

 that very marvellous substance now called "protoplasm." 

 We must leave it to chemists and microscopists to ex- 

 plain its composition and indicate its appearance. Suffice 

 it here to call it, as Huxley did, " the physical basis of 

 life." Without it or when it is dead the plant is dead 

 too ; with it the plant lives, without it it dies. It is a 

 viscid, colourless, jelly-like substance, endowed with all 

 those varied properties which constitute in the aggregate 



