1912] Goodspeed : Nicotiana Hybrids 129 



cut below the bag and brought unopened near enough to the 

 female parent plant to be within easy reach. The copper wire 

 with male label attached is unwound from the neck of the bag, 

 placed upon the field table near by and the bag itself partially 

 opened. The label from the female parent bag is next placed 

 beside the male label and the bag loosened. AVhen the hands 

 have been sterilized the bag is lifted from the castrated flower 

 and laid aside. The pollen parent is taken from its partly 

 opened bag and a pollen-covered anther is extracted with the 

 forceps and applied to the receptive stigma of the female parent. 

 The proper bag is again placed over the pollinated flower 

 and labeled with the original designation of the female 



plant with now in addition the name and sign of the male 



150 5.3 



parent — e.g., 07 5 X ^'i c^- If l^nt one crossing operation at a 



time is attempted, and if the male and female labels are placed 

 side by side during the short period when they are not attached 

 to the plants themselves, there is little danger of mixing the 

 parent labels with subsequent difficulties of identification. 



3. Cleaning of the Seed 



The seed is practically all gathered and dried before Decem- 

 ber 15, is cleaned during February and March and sown late 

 in March and in April. The exceedingly small size and great 

 number of seeds in a single capsule from a Nicotiana plant makes 

 necessary the utmost precautions to prevent contamination in 

 connection with the cleaning and sowing of the seed. During 

 the past three years the seed has been cleaned in a difi^erent 

 room on each occasion. One person is required to do the "book- 

 keeping" and wrapping of the seed envelopes and another to 

 do the actual handling of the seed itself. The bookkeeper lays 

 on a clean table a sheet (4 by 5 feet) of heavy brown manila 

 paper and on it a smaller sheet (12 by 16 inches) of ordinary 

 white paper. The seed cleaner then places a white earthenware 

 saucer upon the white paper and receives the first bag of seed 

 from the bookkeeper. The latter cuts off the tops of the bags, 

 thus opening them and also freeing the seed label. Tie then 



