224 



known that in the latter case, viz. the activity of the plant cells, 

 the influence of light is of the utmost importance. It is true that while 

 plants may grow to a certain extent when deprived of direct sunlight, 

 yet such plants grown in semi-darkness never reach maturity, and the 

 products of their vitality are often quite different from those of the normal 

 plant. In etiolated plants — that is, those grown in the dark — are often 

 found products which do not occur at all in those subjected to normal 

 growth. The action of sunlight is therefore indispensable to the full 

 functional activity of the supraterranean parts of plants. On the other 

 hand, it is seen that the action of sunlight is highly prejudicial to the 

 development of the soil ferments. Exposed to a bright light the activity 

 of these ferments is diminished until it reaches practically the vanishing 

 point. Happily, the surface of the soil being almost impenetrable to 

 light, preserves the organisms lying even near the surface from the de- 

 leterious action of the sun. Warm nights, therefore, are even more 

 favourable to the development of soil organisms than warm days, and 

 all are familiar with the phenomenal growth which many plants make 

 during the night.* 



BENEFIT OF AERATION. 



From what has been said above, it can be inferred that a proper aera- 

 tion is also necessary to the development of the functional activity of the 

 fermentative germs. Gcod drainage and cultivation secure a free circu- 

 lation of air through the soil, and this is essential to the process of nitri- 

 fication, which is simply oxidation procured by low vegetable organisms. 

 While it is important, as indicated above, to remove the excess of water 

 to secure proper aeration, it should not be forgotten that a certain amount 

 of moisture is necessary for the life of the micro-organisms. Experience 

 has shown that when the soil contains from one-third to one-half of the 

 total moisture it is capable of holding, the proper quantity of water is 

 supplied for the most rapid growth of the nitrifying ferments. 



(To be continued.) 



A NATURAL PAPER. 



By S. T. SCHARSCHMIDT. 



This ideal section goes to illustrate how a natural paper is formed 

 and found distributed over the bottom of a natural reservoir, after the 

 water had drawn off. A river when in flood, passes through a Banana 

 Plantation, and carries with it quantities of the banana trash, which it 

 beats into a pulp during its fall of 500 feet, through rocks from A to B 

 as shown. When the reservoir becomes dry, the pulp being insoluble, 

 is found distributed over the bottom, broken up in sheets of various 

 sizes, owing to the contraction when drying. The paper generally has 

 the appearance of thick unglazed packing paper, and sometimes when 

 suspended among twigs in vertical position, is almost as fine and trans- 

 parent as tissue paper completely infolding very fine water grass ; (see 

 Fig. I.) and in other cases as soft and white as cotton wool. 



