PRESIDENTIAL ADDRESS IN SECTION PD. 
BIOLOGY. 
By PROFESSOR A. P. W. THOMAS, M.A., F.L.8., F.G.S. 
In the choice of the subject for a presidential address, much 
latitude is allowed by precedent, and the arrangement is, no 
doubt, an advantageous one from the point of view of the person 
called upon to occupy a position which has its responsibilities as 
well as its honours. An address from the president of one of our 
sections may, it appears to me, take one of three directions: it 
may deal with general topics, or review recent advances in that 
science to which the section is devoted, or it may give a general 
account of work to which the speaker has given special attention. 
The growth of the biological sciences has been so great that. 
even the barest review is impracticable in the compass of an 
hour’s address, whilst the increase of specialisation is so great 
that it can seldom happen that a worker’s own particular line of 
study can be of much interest to all his hearers, whose labours 
probably lie in very different directions. I have refrained, there- 
fore, from choosing a subject suggested by my own research and 
propose to speak to you on more general topics, and more particu- 
larly on that part of the work of this Association which falls to 
the share of those who attend in the section of Biology. 
In the main object of the Association—the advancement of 
science—all sections are interested alike, and in one of the chief 
advantages of our meeting all share alike. Every scientific 
worker needs to meet his fellows ; he is strengthened and stimu- 
lated by talking to sympathetic minds on those subjects which 
engross so large a portion of his intellectual life. If this need is 
felt in England, how much more must it be felt in this new 
Southern world, where the population is scattered, and where a 
man may find himself many days’ travel from the possibility of 
intercourse with those who follow the same branch of study. I 
need not insist on this, for who has not felt the mental stimulus 
of conversation, and been surprised at times with the clearness 
and vigour with which ideas present themselves to the mind 
whilst speaking to one who can give both sympathy and just 
criticism ? 
Further, there is presented in the meetings of this Association 
an opportunity for workers in every department of knowledge to 
discuss and arrive at conclusions on the important topics of the 
