PEDIGREE-CULTURE. 27 



the two plants upon which it has been used. The pollen 

 from the head of one of the plants is brushed into one Syra- 

 cuse watch-glass and instantly covered with another. In 

 this way it is carried to the other plant of the pair and ap- 

 plied carefully to the circle of receptive stigmas. Then the 

 pollen is brushed from this plant into the same dish and re- 

 turned to the first member of the pair, to be brushed upon 

 its receptive stigmas. The dishes are then deposited in a 

 jar of 90 or 95 per cent alcohol, where they remain until 

 the following day, when they are washed and used again. 

 The same brush is used day after day on the same pair of 

 plants until the operation is completed, when it, too, is con- 

 signed to the alcohol jar. In this case, as in all others, the 

 protecting bags are removed from each plant no longer than 

 is absolutely necessary for the performance of each operation. 



In controlling the pollination of Indian corn still an- 

 other method is used. Both ears and tassels are enclosed in 

 paraffin paper bags before the external appearance of stigmas 

 and anthers. Pollen is produced in great quantity which 

 collects in the bag enclosing the tassel. This bag is removed 

 from any plant desired and carried to the plant to be pollin- 

 ated. The silks are uncovered and immediately sifted over 

 with the pollen, which trickles from a small hole torn in one 

 corner of the bag. The silks are then quickly re-covered and 

 the pollen bag is returned to the plant from which it was 

 taken, to be used again the next day or the second day after 

 in a repetition of the process. This work is usually done in 

 the afternoon when almost no pollen is falling from other 

 plants, in order that the entrance of foreign pollen during 

 the momentary uncovering of the silks, shall be reduced to a 

 minimum. 



Probably the most potent sources of error in these vari- 

 ous methods consists: (a) In the possible fertilization by 

 foreign pollen which has been scattered upon the foliage of 

 the plant and so enclosed within the bag; and (b) its intro- 

 duction by the wind or insects in the brief period during 



