134 CIRCULATION OF THE SAP. 



gree of perfection. Some require silicious soils, others a soil 

 containing iime, and others argillaceous or clay soil ; for 

 each plant will be but imperfectly developed in a soil, when it 

 does not find the necessary materials for its organization. 

 Raspail remarks, that "for the reason that a plant would die 

 in a vacuum, for the same reason, would it die in a soil desti- 

 tute of the bases which were necessary for its organic con- 

 stitution. This would be asphyxia for want of soil, as the 

 other is asphyxia for want of air ; for to live is to combine, 

 and without elements no combination would be possible." 

 But in most soils all the necessary elements are found in a 

 greater or less degree. To these facts, the eye of the agri- 

 culturist should be open, and the constitution of his soil 

 should be known, that he may be enabled, as much as is in 

 his power, to supply the deficient element, necessary for the 

 crop he wishes to produce. It is a common coniplaint in al- 

 most every section of country, that some plants uniformly 

 degenerate. In some places it will be one kind, in others 

 another. Now Raspail has shown, that although a soil might 

 be rich in every other respect, but not containing the neces- 

 sary salt for the particular species, the plant uniformly de- 

 generates, and finally ceases to produce seed. The gardener, 

 being aware of this fact, should make such ajW^icatioji as 

 the general nature of his soil seems to indicate. 

 "' 176. We should be glad in this place, to extend our obser- 

 vations on manures, drawn from the writinajs of De Candolle, 

 Raspail, Dutrotcliet, Davy, Boussingault. I'haer, and various 

 authors of our own country, but our space lorbids it. The 

 subject would afford matter for a treatise by itself. 



Section 7. Circulation of the Snp, 



177. Within the last few years m-uch has been accomplished 

 in this department of vegetable physiology. The circulation 

 in the cellular tissue, we noticed under the description of that 

 tissue, and it will be unnecessary to notice it farther in this 

 place. That is called the circulation of Rotation, There 

 are two well distinguished kinds of circulation. General and 

 Special. The one above noticed, is of the latter kind* 



178. That there is a general circulation from the roots 

 to the leaves, is plainly indicated by the rapid evaporation 

 which is constantly going on from the surface of those organs. 

 How soon does a vigorous plant wither and diminish sensibly 

 in weight, when cut in the mid day sun? And plainly for no 

 other reason, than that the source of its supply of fluid is cut 



