126 PLANT LIFE ON THE FARM. 



possible in the case of an analogous injury done to one 

 of the higher animals. The lower the organism, the less 

 special in its conformation and construction, the more 

 independent are its constituent cells. The higher the 

 organism, and the more specialized its structure, the 

 more dependent one upon another are the structural ele- 

 ments of which it is compounded. 



Natural death may be described as an exhaustidn of 

 the protoplasm its water evaporates or is drafted else- 

 where ; and so with its soluble or liquid contents the 

 insoluble and the useless remain behind. We see this in 

 the case of the leaves every autumn ; their protoplasm 

 dries up, their chlorophyll degenerates and disappears ; 

 they are emptied of starch and other matters, which are 

 conveyed to some other part of the tree to be stored up 

 for future use by the new growths in the following sea- 

 son, until at length nothing is left but a framework of 

 dry cellulose, a quantity of mineral or earthy matter, and 

 such material as could not be dissolved or transported. 

 In other organs the continuous maturing process at 

 length results in the blocking up of the cells and tubes 

 by continued deposit in the interior. Osmosis can no 

 longer go on between them, for their altered structure 

 prevents it, and in consequence the protoplasm disap- 

 pears. Just as in human beings, the minute blood-ves- 

 sels get " bony " or otherwise deteriorated in structure, 

 so do the cells and fibres of plants become unfit to carry 

 on the processes of life. 



For the purposes of the cultivator, it is very desirable 

 that he give an eye to the way in which plants die and to 

 the causes in which induce death. The subject may be 

 looked at from various points of view. From the struc- 

 tural point of view, death may begin in the cells of the 

 root, in those of the stem, in those of the intermediate 

 "collar," or in those of the leaves, and the appearances 

 presented will be found to differ correspondingly. 



