10 



the superior individuals are permitted to grow side by side, 

 while the insects and winds are busy blending the two 

 together by means of the transmitted pollen, and, of course, 

 the healthy plants suffer to the advantage of the inferior 

 forms. The seed thus produced become greatly deteriora- 

 ted in the course of a few years, and the farmer is ready to 

 heap denunciations on the head of the man from whom he 

 bought the improved seed a few years before, at a high 

 price. It does not pay to cultivate inferior grades of cotton 

 in the neighboring fields where improved cotton is growing. 

 Insects will soon transmit pollen from one grade to the 

 other so as to cause the fine seed to greatly lose its vitality 

 and superior qualities, and soon cause it to retrograde to 

 the original inferior stock from which it had been improved. 

 An intelligent, observant man, standing in a cotton field 

 during a bright, warm morning, in July or August, will 

 notice humming birds and many insects busy flying from 

 flower to flower sucking the nectar for food. A close exam- 

 ination of the bodies of these insects will disclose the fact 

 that over th'em is scattered quantities of pollen. When the 

 insect crowds down into the corolla cup to reach the nectar 

 at its base, the pollen on its body is attached to the stigma 

 and fertilization is accomplished. Now if the insect has 

 visited the flowers of inferior grades of cotton before reach- 

 ing the improved flower, the inferior pollen will have a 

 chance to put in its effects on the germ of the improved cot- 

 ton. All seed should be carefnlly selected each season ; and in- 

 ferior plants noted in the field should he rooted out before they 

 begin to bloom. 



With these facts concerning the development of the flower 

 well understood we are prepared to enter upon the discus- 

 sion of the results secured from the experiments in crossing. 



METHODS ADOPTED IN THE FIELD FOR PEODUCING THE CROSSING. 



The term "crossing" in botany signifies the blending of 

 two varieties of the same species by transmitting the pollen 

 of the flower of one form to the pistil of the other. In this 



