82 QUIHCE CULTURE. 



and friends. The two trees had been ten years planted, 

 and show what can be realized from the most favorable 

 conditions of growth and marketing. From the prices 

 reported in several other States, the successful cultivator 

 of this fruit could not fail to make it profitable. 



CHAPTEE XVII. 

 DISEASES OF THE QUINCE. 



DISEASES in trees arise from a variety of causes, such 

 as insect depredations, loss of vitality from bacteria, and 

 fungi preying on the living tissue; or there may be organic 

 disease reproduced from unhealthy stocks and seeds. 

 One form of existence is destroyed to produce another. 

 The elements of life by death and decay enter into new 

 forms of life. Disease in one department of nature may 

 provide for a want in another. 



The chief known causes of disease in quinces are 

 bacteria and fungi. They are both low forms of vege- 

 table life, the first multiplying by the division of a single 

 cell, the second producing several spores in a cell. Of 

 the various bacteria, each acts in a way peculiar to itself. 

 Some produce disease, some act as ferments, others assist 

 in the ripening of fruits, and still others aid in the re- 

 generation of organic matter to form cell-structure. 



The fungi are cellular, flowerless plants, which receive 

 their sustenance from the earth or the organized bodies 

 on which they grow. They differ from other plants, in 

 general, in chemical composition, being chiefly nitrogen 

 instead of carbon ; and in their method of growth, ab- 

 sorbing oxygen and giving out carbonic acid. All the 

 higher forms of plant life may have one or more of these 

 low forms to prey on it as a parasite by its absorbing 



