142 MASSACHUSETTS HORTICULTURAL SOCIETY. 



alone from the deca3'ing matter of the soil, but from the air as 

 well. Both air and water, in their circulation through a carbona- 

 ceous soil, readily part witli their fertilizing gases to this greedily 

 absorbing agent. It also gives power to the soil to absorb moist- 

 ure, because it is itself an absorbent of water. We all know with 

 what great rapidity peat}'^ soils, which are simply carbonaceous soils, 

 absorb moisture, and with what evident reluctance the}' part with 

 it. Decayed vegetable matter darkens the soil, rendering it 

 warmer ; for we all know that a dark surface will absorb more of 

 the sun's rays than a light one. A dark coat is warmer to our 

 backs than a white one, although of the same weight and texture. 

 The decay of vegetable matter is always accompanied by the evo- 

 lution of heat, — perhaps not sensible to our feelings, but the 

 rootlets of the growing plant realize it and are quick to respond to 

 it. Is there not food for reflection here? Is our little leaf to be 

 despised when its changes and many influences are thus traced out? 

 I think not, for it opens the whole theory of the application of 

 manures, either of our barn-3'ard composts, or of the so-called 

 commercial fertilizers. 



Aside from its utility in agriculture, we can view carbon as a 

 wonderful curiosity' of nature, for in its universality of condition 

 we find it varying from lampblack, with its velvety softness, to 

 the unyielding hardness of the brilliant diamond. 



The grasses of the world, over six thousand species, or nearly 

 one-sixth of all the flowering plants, can legitimately come within 

 the subject of our inquir}-, for they are leading crops in most sections. 

 The principal point is that a leaf, when grown, never changes its 

 form or size, and that when quickly grown its size is far larger 

 than when its formation is slower. The leaves of grass follow this 

 rule ; hence would we have large grass we must grow it quickly, 

 producing a large leaf, valuable not alone for itself, but because it 

 also adds to the volume of the stem. 



The fruit culturist will thoughtfully consider the subject of 

 pruning in its relation to the proportionate capacity of the leaf 

 to the plant and the fruit, and will guard his knife accordiugl}'. 



The anatomy of all leaf}' structures ; the physiology depending 

 thereon, including absorption and imbibition ; the circulation of 

 nutritive fluids; respiration, exhalation, nutrition or growth, 

 secretion, the evolution of electricity and heat, and the chemistrj^ 

 of leaf action, should all be familiar ground to the agriculturist, 

 for tlie leaf is the most important portion of the plant, — the busi- 



