RESEARCH SEMINAR. 249 



and used in practice long before the rediscovery of Mendel's 

 works. 



The fixation of select hybrids into stable races is best accom- 

 plished by isolating the progeny of the select plant and breeding 

 together those individuals of the progeny which are nearest alike. 

 Probably fixity or uniformity could be gained quicker by in and in 

 breeding, but in plants that are normally cross fertilized the loss 

 of vigor and fertility from the inbreeding would probably in most 

 cases render the use of this method impractical. 



Attention was directed to the important improvements that 

 can be secured by the selection of vegetative parts. By the 

 selection of vigorous growing cuttings of the carnation, violet, 

 rose, etc., the size and number of the flowers produced can be 

 greatly increased. Many bud sports or bud mutations have 

 been used as new varieties and are valuable acquisitions. 



Plant breeding, it was pointed out, is not necessarily a difficult 

 task. The speaker urged the great importance of the work and 

 the necessity of more extensive scientific investigations and prac- 

 tical experiments. 



August 5. Cytoplasmic Structures of the Plant Cell. By 



BRADLEY MOORE DAVIS. 



The writer described in this seminar the principal structures 

 and activities of the cytoplasm in different parts of the plant cell 

 and at different periods of ontogeny. There are three principal 

 regions of the cytoplasm: (i) The plasma membranes (kino- 

 plasmic in character), which surround the protoplast, the vacu- 

 oles and the nucleus, (2) trophoplasm, and (3) the kinoplasm 

 intimately concerned with mitotic phenomena and which finds 

 morphological expression in asters, centrospheres, centrosomes 

 and filarplasm. The structure of trophoplasm was described 

 together with the peculiar physodes, nematoplasts and cceno- 

 centra. But the main discussion concerned the behavior of kino- 

 plasm during mitosis and the segmentation of the protoplasm at 

 cell-division. Many of the kinoplasmic structures characteristic 

 of these events may be closely related to one another, in spite of 

 their diverse morphology, when studied ontogenetically, and the 

 author discussed some of these problems with especial reference 

 to his studies on the Hepaticae and Thallophytes. 



