STATE milTIJULTURAL SOCIETY. 279 



Still farther advancing, we pass through a bell of conifers — firs, larches, pines and 

 other qi edle leaved tree*, and these leading through a range of birches, which become 



more and more stunted, introduce us to a region Ol mosses and saxifrages, but which, 

 al length, has do tree nor ahrub ; and finally, a.-> the perpetual polar ices are reached, 

 the red mow alga la the last trace of vegetable organization. 



The deduction* we draw from the premises laid down are these: 



Fir.-t. The growth of plants is dependent on physical causes. 



Second. The agencies operating to produce these reaulta, are heat, air and water, 

 and to these muat be added another, which is light; for if growth be couducted in 

 darkness, heat, air and water cannot cause the youug plaut to add anything to its bud- 

 stance, (for it is feeding on the seed.) 



Therefore, growth in darkness leads to one result, and growth in the sunshine to 

 another. 



In addition to the physical agencies spoken of, there is an innate or plastic power 

 which resides in the germ, and although the seed may be kept in a dry place for many 

 years, without undergoing any visible change or losing its power of germination, yet 

 when these agents are brought to bear upon it, there is at once an attempt at evolving 

 its parts —in other words, it begins to grow. 



The organic series presents a noble aspect. Every member of it, even the humblest 

 plant, is perfect in itself. From a common origin, a simple cell, all have arisen. 

 Viewed under the most powerful microscope there can be no difference detected in the 

 primoidal or first cell, which is to produce the lowest plant and that which is to pro- 

 duce the highest ; but the one, under the favoring circumstances to which it has been 

 exposed, has continued in the march of development, the career of the other has been 

 Stopped at an earlier point. 



J lad ih ■ e agencies, which have been at work, varied, that variation would have been 

 expressed in the resulting form and function. 



Experiments have demonstrated that every cultivated plant requires a certain quan- 

 tity of beat lor its development, but is is the same thing, whether this heat is distribu- 

 ted over a shorter or longer space of time, so that certain limits are not exec ded. 



Example of this: Along the banks of the Nile, in Egypt, the time for sowing barley 

 is the latter part of November, and it is harvested at the end of February. In various 

 other places, both upon the eastern and western continents, the time for planting this 

 cereal is from February to June, and it matures in frmo three to five months, yet the 

 same amount of heat is required. 



This is also true with reference to light, as Berzelius has most graphically said, when 

 speaking of Northern Europe, where, during the month of June, the sun never sets 

 he says that under the influence of this fiitdnfght tun of the north, the life ol plant* 

 runs through the same cycle of change in six weeks which it takes four or live months 

 to accomplish in beautiful Italy. 



The effect of rain upon plants is two fold : It exerts, over the carbonic acid gas of the 



air, a solvent power, carrying it into the ground for their nourishment ; it also brings in 



larger quantities i<> the Interior of the .saline constituents of the soil, which arc required 



for tissue de\ ulppment, 



The chemical constitution of soils has great Influence in affecting the well-being of 



plants ; for we should scarcely expect I ba1 seaweeds, into the composition of which bro- 

 mine and iodine enter, should ever grow where these chemical elements are totalh 



