VEGETABLE PHYSIOLOGY. 81 



disease that discovers itself in the contortion or convolution of 

 the margin, or wrinkled appearance of the surface. The leaves 

 of the apricot, peach and nectarine, are extremely liable to be 

 thus affected in June and July. The leaf that has been 

 punctured soon begins to assume a rough and wrinkled figure, 

 and a reddish and scrofulous appearance, particularly on the 

 upper surface. The margins roll inwards on the under side, 

 and inclose the eggs which are scattered irregularly on the surface, 

 giving it a blackish and granular appearance, but without 

 materially injuring its health. In the vine the substance deposited 

 on the leaf is whitish, giving the under surface a sort of a frosty 

 appearance, but not occasioning the red and scrofulous aspect 

 of the upper surface of the leaf like that of the nectarine. 



Sometimes the upper surface of the leaf is covered with 

 clusters of wart like substances somewhat subulate and acute. 

 They seem to be occasioned by means of a puncture made on the 

 under surface, on which a number of openings are discoverable, 

 penetrating into the warts which are hollow and villous within. 



11. Consumption. From barren or improper soil, unfavora- 

 ble climate, careless planting or too frequent flowering, exhausting 

 the strength of the plant, it often happens that disease is induced 

 which terminates in a gradual decline and wasting away of the 

 plant, till at length, it is wholly dried up. Sometimes it is also 

 occasioned by excessive drought, or by dust lodging on the 

 leaves, or by fumes issuing from manufactories which may happen 

 to be situated in the neighborhood ; or by the attacks of insects. 



There is a consumptive affection that frequently attacks the 

 pine tree, called Tepedo pinorum, which affects the alburnum 

 and inner bark chiefly, and seems to proceed from long continued 

 drought, or from frost suddenly succeeding mild or warm 

 weather or heavy winds. The leaves assume a tinge of yellow 

 bordering upon red. A great number of small drops of resin 

 exude from the middle of the boughs of a putrid odor. The 

 bark exfoliates, and the alburnum presents a livid appearance. 

 The tree swarms with insects, and the disease is incurable, 

 inducing inevitably the total decay and death of the individual. 

 11 



