SCIENCE 



Friday, Februaby 27, 1914 



CONTENTS 

 T'lie American Association for the Advance- 

 ment of Science: — 



The Evolution of a Botanical Problem: 

 Pkopessoe Duncan S. Johnson 299 



J, J. Rivers: Pkopessoe Ira M. Btjell 319 



The Fourth International Botanical Congress. 320 



The American Society of Naturalists 322 



Scientific Notes and News 322 



and Educational News 325 



discussion and Correspondence: — 



Graduate Work in American Universities: 

 EuDOLP PiNTNER. The Cause of the Pe- 

 culiar Sound made iy NighthawTcs when 

 Volplaning : Frank A. Hartman 326 



Scientific BooTcs: — 



Lohnis on Landwirthscliaftliche Bacterio- 

 logie: De. P. G. Heinemann. von Koiells 

 Lehrbuch der Mineralogie: Professor Ed- 

 ward H. Keatjs. Getman's Theoretical 

 Chemistry: Peopessor Victoe Lenhee .... 327 



Botanical Notes: — 



Smell's Manuals; Notes: Propessoe 

 Chaeles E. Bessey 329 



Special Articles: — 



Mitochondria in Tissue Cultu,re: M. E. 

 Lewis, Dr. Warren H. Lewis 330 



The Astronomical and Astrophysical Society 

 of America: Peopessoe Philip Fox 333 



Societies and Academies: — 



The Academy of Science of St. Louis: Pro- 

 fessor G. O. James 334 



MSS. intended for publication and books, etc., intended for 

 review sliould be sent to Professor J. McEeen Cattell, Garrison- 

 on-Hudson. N. Y. 



TSE AMERICAN ASSOCIATION FOB TEE 

 ADVANCEMENT OF SCIENCE 



TSE EVOLUTION OF A BOTANICAL 



PROBLEM 



THE HISTORY OP TIIE DISCOVERY OP 



SEXUALITY IN PLANTS^ 



From the beginning of man 's thoughtful 

 consideration of natural processes, the phe- 

 nomenon of sexual reproduction, with the 

 associated phenomena of heredity, have 

 persistently engaged his keenest interest. 

 The primary fact of the necessary concur- 

 rence of two individuals in the production 

 of offspring was, in the case of animals, 

 recognized from the beginning. The equiv- 

 alent phenomenon was not established for 

 plants until the end of the seventeenth 

 century. At this time, however, little more 

 was known of the essential features of the 

 sexual process in animals than had been 

 familiar to Assyrians, Egyptians and 

 Greeks twenty centuries before. 



Of the additions made since 1700 to our 

 knowledge of sexual reproduction, of its 

 varied types and of the associated phe- 

 nomena, no mean share has been contrib- 

 uted by botanical investigators. Note- 

 worthy among such contributions are the 

 work of Koelreuter and Mendel in the pro- 

 duction and systematic study of plant hy- 

 brids, and the early work of Pfeffer on 

 the chemotactic response of spermatozoids. 

 Of more recent work we may cite that of 

 the plant cytologists on apogamy and 

 apospory, on multi-nucleate sexual cells 

 or gametes, and on the long-delayed nu- 

 clear fusion in the sexual reproduction 



1 Address of the vice-president and chairman of 

 Section G, Botany, American Association for the 

 Advancement of Science, December, 1913. 



