Section D. 



(BIOLOGY.) 



President of the Section — Professor William A. Haswell, M.A., 

 D.Sc, F.L.S., Cballis Professor of Biology, Sydney University. 



ADDEESS BY THE PRESIDENT. 



Becent Biological Theories. 



I HAVE chosen for the theme of the following address, as likely 

 to be of interest to most of the members of Section D, the sub- 

 ject of recent theories in biology — the new theories or new 

 modifications of old theories that have found the light in the 

 course of the last year or two. To treat such a subject at all 

 adequately and completely would require not a single address, 

 but a long series of lectures ; and, without attempting a com- 

 prehensive treatment, I purpose merely selecting certain parts 

 of the subject which appear to me the most interesting and 

 the most important. 



It is not so very long since the word " theory " was almost 

 anathema to the vast majority of the students of plant and 

 animal life. True, there were always theorists ; but, with the 

 few" brilliant exceptions in which a capacity for theory was 

 combined with a talent for observation, these were looked upon 

 with suspicion, not always untinged with contempt. The 

 naturalist of the old school went plodding along, accumulating 

 his descriptions of species and his records of remarkable and 

 interesting facts, without much thought of theoretical explana- 

 tion. He was content to take "short views" of things, and 

 found his satisfaction in the indulgence of a passion for the 

 piling- up of concrete particulars — a passion which must ever 

 be one of the mainsprings of activity in the investigation of 

 nature, but which has not been the strongest motive in the 

 eases of those whose names are most likely to be remembered. 

 Theory, in fact, was later in finding its way, as regards the 

 main body of workers, into this than into any other depart- 

 ment of science." It is, it need hardly be said, mainly to the 



* This is true, of course, only as a general statement, and there have 

 been some exceptions. The theorists of the "nature-philosophy " school, 

 for example, at the beginning of the present century, seem not to have 

 been without influence on the scientific workers of their time. 



