THE WHEAT CROP. 71 



or identify them. Many of them live within the very 

 substance of certain plants, encased beneath the epidermis 

 (scarf-skin). In the progress of their growth, they raise 

 small blisters under the epidermis (as in rust and mildew), 

 and when arrived at maturity, they burst through it, and 

 then form spots or irregular blotches of various colours, 

 which have different hues according to their peculiar na- 

 ture, and are seen usually red, orange, brown, or black. 

 Now, these spots are masses of fructification, and are sur- 

 rounded by the tattered edges of the ruptured skin. A 

 large number are known to botanists, and like animals of 

 a parasitic nature, they seem to be restricted in their 

 mode of attack, being able to live on certain species only, 

 and sometimes even then, only on particular parts of par- 

 ticular individuals of these species. In parasitic animals 

 the same peculiarity is seen ; some live only in the skin, 

 others beneath it; some in the bowels, and others again in 

 the substance of the muscles and the flesh. Some of these 

 fungi confine their attacks to the seed, as the U. caries; 

 others again, as the U. segetum, to the short stalk or 

 pedicel on which each flower is placed; whilst others, 

 as the U. Rubigo and the Puccinia graminis, are re- 

 stricted in their range to the stem, leaves, and chaff-scales 

 of the plants they take possession of. All of them, how- 

 ever, commence their existence beneath, and not upon the 

 epidermis. 1 



We must now pass on to another class of injuries to 

 which " our Farm Crops" are liable that due to the attacks 

 of insects. These are, happily, more readily recognized, 

 and less mysterious in their agency, and therefore have 

 generally made more impression on, and received more 

 attention from the agricultural community. The valuable 



1 A very comprehensive and interesting account is given of these diseases, 

 in a little work by the Rev. E. Sidney, entitled, the Blights of Wheat, and their 

 Remedies, published by the Religious Tract Society. 



