135 



Canada; Dr. Ora M. Clark, 110 North Pecan St., Bristow, Okla. ; 

 Mr. Carl O. Grassl, Division of Sugar Plant Investigations, Bureau 

 of Plant Industry, Washington, D. C. ; Dr. Tobias Lasser, 629 

 Forest Ave., Ann Arlx^r, Mich. ; Dr. Harold L.. Lyon, Experiment 

 Station, H. S. P. A., Honolulu, Hawaii; Mrs. R. Burnside Potter, 

 Smithtown, N. Y. ; Dr. Louis Harry Roddis, Hospital Corps School, 

 San Diego, Calif. ; Dr. Paul B. Sears, Oberlin College, Oberlin, O. ; 

 Mr. John A. Stevenson, 4113 Emery Place, N. W., Washington, 

 D. C. ; Dr. F. W. Went, California Institute of Technology, Pasa- 

 dena, Calif. ; Dr. Eula Whitehouse, Texas Memorial Museum, 

 Austin, Tex. ; and Dr. Kenneth E. Wright, French Road, King- 

 ston, R. I. 



Three candidates were elected to associate membership : Miss 

 Annette Hochberg, 251 West 89th St., New York; Mrs. Warren 

 Kinney, Morristown, N. J. ; and Miss Marion L. White, 258 Lafay- 

 ette Ave., Passaic, N. J. 



The scientific program consisted of a lecture by Professor E. 

 W. Sinnott on "Some Problems of Cell Behavior in Plant Develop- 

 ment." The speaker's abstract follows : 



"An understanding of the mechanism of plant development requires a 

 knowledge of the activities of cells during growth. Three aspects of cell 

 activity have recently been investigated in our laboratory as follows : 



(1) Roots of small-seeded grasses grown on damp paper may be ex- 

 amined with the high power from time to time and their growth studied in 

 terms of cell size and cell number by means of camera lucida drawings. Such 

 studies make it clear that (a) cells do not slide past each other during growth, 

 (b) the newly formed cell walls are never opposite walls of adjacent cells, (c) 

 the cell grows at different rates in its various parts, and (d) cell enlargement 

 after division ceases begins first at its basal end and progresses toward the 

 apex. 



(2) Measurements of cell size and cell number in developing cucurbit 

 fruits show that the innermost tissues as compared with the outer have cells 

 which reach a larger size before division ceases, and that they cease division 

 earlier. Small fruited types as compared to large ones have somewhat 

 smaller cells both before cell division ceases and at the end of cell expansion ; 

 and division in all tissues ceases at about the same time in small types but is 

 spread over a much longer period in large ones. 



(3) Changes in shape of fruit during development is related to differences 

 in plane of cell division. This was studied particularly in wounded tissues 

 and here it was found that the first indication of the plane in which a cell was 

 to divide was provided by an aggregation of cytoplasm in approximately the 

 plane of the first cell wall." 



