56 THE WHEAT CULTUKIST. 



may be found in every stage of formation, from perfect 

 liquidity to a solid. Perhaps an inch from the outside 

 of the issue of thf mould, the lead is in a semi-plastic 

 state. A little farther up, the lead tube is in a semi 

 fluid condition. On the upper side of the joints of 

 wheat straw, down in the sheaths, which fit the straw 

 cylinders perfectly air-tight, the material which forms 

 the straw is in a liquid state. The sheath is the mould, 

 and the straw is the piston. By the A 7 ital expansion of 

 the liquid above the joints, the length of the straw i? 

 increased between them, so that the upward growth o^ 

 the plant takes place above every joint. If there be six 

 joints in one straw, and the length of each is increased 

 only one-eighth of an inch in twenty-four hours, the 

 head of grain will be elevated above the roots three- 

 fourths of an inch per day. 



These facts in vegetable physiology will enable us to 

 understand why the stalks of Indian corn often grow 

 more than two inches in height in less than a day; 

 and we perceive, also, something of the practical im 

 portance of having an abundant supply of nourishment 

 for the roots of the growing wheat to take up and ap 

 propriate to the growth and development of the straw, 

 at that critical period when portions of the straw are in 

 a liquid state ; as the wheat plant cannot lay up in store 

 plant food to be employed in promoting the growth of 

 the various parts at the time when the pabulum is 

 needed most. The growth of wheat plants suggests 

 many interesting thoughts to which I shall not allude, 

 as the purpose of this treatise is primarily to bring 

 out items of a practical character, without burdening 

 the reader with interesting theories of no practical 

 utility. 



