140 MASSACHUSETTS HORTICULTURAL SOCIETY. 



in view then, we will content onrselves with the simple statement 

 of the phenomena of animal respiration, without going at all into 

 its interesting details. In the act of respiration the animal absorbs 

 oxygen from the air b}' means of the blood cells, or disks, which, 

 so to speak, come in contact with it as it is spread out in the 

 tissue of the lungs. At the same time that it absorbs its oxygen 

 it liberates large quantities of carbonic acid gas. Vegetable res- 

 piration is the reversfc of this : ox3-gen is eliminated, and carbonic 

 acid gas received. Thus are the two kingdoms of the organic world 

 dependent upon each other, the plant furnishing the ox^ygen that 

 the animal consumes, and the animal the carbonic acid that the 

 plant consumes. Is there not an evidence of reasoning and design, 

 from some source, in this arrangement? 



But the question that comes most pertinently home to us today 

 is. How are we, as farmers and horticulturists, to derive any benefit 

 from a knowledge of leaf physiology? How are our acres to be 

 benefited thereby? Can we insure better and larger crops? I 

 answer, most assuredlj', Yes, if we will systematically put in prac- 

 tice the ideas we gain from a study of our subject ; not only indi- 

 vidually, but collectively, for oftentimes if we would profit by 

 Nature's laws we must enact state and national laws to harmonize 

 with them. 



Let us take an example of the latter point. We have all of us 

 suflfered more or less from the effects of drought, and we hear much 

 said in connection, therewith regarding the preservation of our 

 forests. The press of the country, both agricultural and general, 

 is filled with it at times. The leading arguments seem to be that 

 the dank, moist atmosphere of our woodlands is occasioned b}' the 

 deep shade from the foliage preventing the sun's warm rays from 

 penetrating and dispersing it by evaporation, and that the soil of 

 woodlands is also protected from the parching effect of the sun's 

 influence and from drying winds ; consequently' such soils prove to 

 be reservoirs for water, and in time of drought will keep the streams 

 well fed. Undoubtedly these views are correct, and forests do 

 pla}' important parts in lessening the injurious effects of drought ; 

 but to my mind there is a stronger reason yet why these leaf 

 treasuries should be carefully guarded. We have seen that the 

 surface of the leaf is abundantly supplied with mouths, or pores, for 

 the transpiration of sap. Numerous experimenters have investi- 

 gated this subject, and have placed on record many interesting facts 

 connected therewith, which go to show that the quantity of pure 



