Epidemics. 255 



tion, let us return back to the present epidemic epoch. It 

 it be supposed that an idea is entertained that the great 

 change in vital manifestation is shown only in the heart, 

 as a leading centre of disease, such a notion would be very 

 incorrect ; for though the nutritive processes of the body, 

 in its molecular cell growth, is by far too intricate a subject 

 for existing scientific appliances to reduce to anything like 

 an appreciable matter of fact, yet an entire survey of animal 

 and vegetable stock, reference being had to our cultivated 

 plants and our domesticated animals, will lead to a some- 

 what singular conclusion. 



Since 1817 few of our species or kinds of potatoes are in 

 existence which were favourites with the growers before that 

 time, or even as late as 1832. The old kinds either are 

 subject to the existing* potato disease of 1846, or they are 

 less productive, or are uncertain in their yield ; hence new 

 kinds have taken their place. 



The same stands good of our strawberries, goose- 

 berries, and more recently of our currants and rasp- 

 berries. 



The apple of Henry VIII. , and of the Stuart dynasty, 

 stood the test for generations, and perhaps apples of a finer 

 flavour, or trees of finer growth and of greater productive 

 powers, it is impossible to conceive ; but now they are all 

 either dying out, or from woodiness of flavour, or too great 

 tartness, are entirely rejected nay, their meagre productive 

 powers are too scanty to view them otherwise than 

 cumberers of the ground, and fresh grafts from old stock 

 are anything but satisfactory, on the grounds of meagre 

 productiveness. 



Of course, pears, plums, and cherries are placed in the 

 same general category. The cherry tree, though a tough 

 and enduring wood, and very productive, yet the fruit is 

 now slowly giving way to the introduction of new and better 



