4A THE WHEAT CULTTJKIST. 



while a particle of this is near. Impregnation takes 

 place best when the weather is dry and warm, as a pecu- 

 liar warmth, and a certain electric state of the atmos- 

 phere, prepare the parts for this process, which always 

 occurs on a dry day. The opinion, indeed, has been ex- 

 pressed, that the pollen of the male conveys hydrogen 

 to the ovules of the female ; that oxygen is received from 

 the atmosphere, and carbon, in the form of carbonic 

 acid gas, from the roots ; and that, when the pollen is 

 destroyed by the rain, or from any other cause, the 

 carbon alone is found in the ear; and this is the well- 

 known ' smut ' in wheat. That pollen of the stamen is 

 essential to impregnation is at least certain ; and it is al- 

 most as certain, from what has been stated, that the total 

 destruction of the reproductive power of a particular 

 race of wheat must be effected, before the influence of 

 another can be felt. Two races being placed together, 

 therefore, a cross can only be certainly effected by clipping 

 the anthers from all the stamens of one variety, and leav- 

 ing the work of impregnation to be effected by those of 

 the other exclusively. This may be done by any person 

 capable of distinguishing between the two races ; but, 

 perhaps, the safer guide to this distinction consists in 

 sowing the two in separate drills, very near each other, 

 say nine or ten inches apart ; and to render the work 

 still more sure, there should be no other growing wheat 

 within at least a quarter of a mile of that experimented 

 upon, the affinity between the pollen and the ovules 

 being of almost incredible force. 



"As soon as the anthers show their first rudiments, 

 in a race upon which the cross is to be made, they 

 should be carefully removed, or clipped with a pair of 

 sharp scissors, leaving the female organs undisturbed. 



