DISEASES. 161 



family, and at the same time was something of a student of 

 comparative anatomy and physiology, tracing analogies be- 

 tween the animal and vegetable kingdoms, should be famil* 

 iar also with the diseases of plants. Such an anticipation, it 

 is feared, will not, in the present instance, be realized. In- 

 deed, the writer feels very much at a loss how to proceed 

 in discussing this branch of the subject, and hardly knows 

 what departiares from undoubted health and vigor should 

 be considered worthy of the title of disease. Nor is it 

 easy to trace the causes of the conditions that are gener- 

 ally viewed in the light of maladies. "We find the mani- 

 festations both in the tree or plant, and in its several parts, 

 and also in the products which chiefly interest us ; the fruits 

 themselves, are often deterioi-ated by what is called dis- 

 eased action of diflFerent kinds. The analogy to diseases 

 of animals is certainly not very distinct. We do not find 

 anything like fevers, or gout, or rheumatism, in plants, but 

 we may consider some of their conditions somewhat in the 

 light of dropsies, and plethora or hypertrophy oij the 

 one hand, and of anaemia or atrophy upon the other ; wo 

 may consider canker and the death of some parts /of a 

 plant analogous to gangrene, and mortification in the ani- 

 mnl subject. Then again we find congenital defects in in- 

 dividuals among plants, just as we do among animals. 

 Some are always less vigorous than others, and thus cer- 

 tain varieties seem possessed of a degi'ee of inherent dis- 

 ease that perpetually prevents them from displaying the 

 requisite strength and vigor which we so much desire in 

 our plantations. Certain varieties that, from the size and 

 excellence of their fruits, have attracted the attention of 

 pomologists, are so deficient in health and vigor as to be 



