Inheritance in Gametophytes 131 



the question of technique. It might be asked how one 

 could breed such a form as Ulothrix, in which the pro- 

 ductive cells are microscopic and are practically impos- 

 sible to identify or even to isolate successfully. One 

 could begin with such a form as Spirogyra, however, 

 in which the zygotes are rather large cells, so large 

 that they can easily be detected without a microscope. 

 Two biologists, BARBER (i) and KITE (3), by using fine 

 pipettes, have been able to isolate bacteria successfully 

 and even to drag individual chromosomes out of nuclei. 

 It would be far simpler to isolate the zygotes of Spiro- 

 gyra. Incidentally, it may be mentioned that the 

 zygotes of Spirogyra are sometimes produced by the 

 union of three sexual cells instead of two, and breeding 

 results in such a case should be very interesting. 



For the following two reasons, therefore, a study of 

 inheritance in gametophytes is demanded and should 

 be undertaken: (i) to test our hypothetical mechanism 

 with its segregation of many kinds of factors; (2) to 

 study the lower plants where breeding phenomena are 

 not obscured by so many complexities. 



In a secondary way, also, the gametophyte generation 

 becomes significant in genetics. . Under the topics 

 of self-sterility, xenia, and hybrid vigor, inheritance 

 in gametophytes will be touched upon again. The 

 preceding discussion has been merely a suggestion of 

 the perspective of an entirely new territory for explora- 

 tion, a territory which should be made a part of that 

 which is already occupied. 



In conclusion, the following quotation from EAST (2) 

 is pertinent: "Modern discoveries tend more and more 

 to show that the sole function of the gametophyte of 



