704 



the sheath usually covers the stem, the injury caused by this blight is 

 scarcely perceptible. 



The effect of this fungus when on the straw is to divert the sap 

 from its proper channel, to waste it in supporting a parasite, and thus 

 to starve or impoverish the grain, which nevertheless always ripens, 

 although sometimes so reduced as to produce little else than bran 

 when it is ground. In all fruits and vegetables that have long been 

 under the care of man, and applied to his uses, the fleshy and nutri- 

 tious parts have been purposely and studiously increased. The ap- 

 ple, pear, plum, cabbage, turnip, and carrot are familiar illustrations 

 of this fact. And, although we are unacquainted with wheat in a na- 

 tural state, or, as it is termed, as a wild plant, it may be assumed that 

 the quantity of flour contained in a grain of wheat has been greatly 

 increased by cultivation. It is certain that Nature does not require 

 so much for the healthy germinating of the seed ; for every grain of 

 blighted wheat (I speak of this rust, or straw-blight) will germinate 

 readily ; and the plant which it produces has no predisposition for 

 blight. There is, therefore, a positive advantage in procuring thin or 

 starved wheat for sowing, because an infinitely greater number of grains 

 go to the bushel. It is, however, the general, and, I may add, the 

 unwise, practice to select plump wheat for seed, thus sacrificing an 

 immense amount of human food, and gaining no proportionate advan- 

 tage as regards the future crop. I have often seen the light wheat 

 given to fowls, as not being good enough to use as seed. The flour 

 in a grain of wheat is doubtless provided for the especial purpose of 

 nourishing the young plant until it can draw nutriment from the air, 

 and from the soil. Immediately the spark of vitality is called into 

 action, the seeds send a little spear, or plumule, upwards to the air, 

 and a little root, or radicle, downwards into the ground. But for 

 some days, and while these are growing most rapidly, they derive no 

 support from extraneous objects ; and it is then that the flour con- 

 tained in the grain constitutes the food on which they live. But 

 this flour is required only for a short time, and in small quantity; 

 for as soon as the infant plant can feed on extraneous fluids it no 

 longer requires the flour in the grain, and consequently whatever ex- 

 ceeds the exact quantity required uiust be wasted. Tiiis fact in vege- 

 table physiology should ever be remembered by the farmer. 



When a great and obvious injury is done to us, the discovery of 

 the source, or cause, or author of that injury is a necessary preliminary 

 step to prevention. If a house is robbed, and we discover the thief, 

 we have achieved something towards a prevention of the recurrence 



