PREFACE 
The influence of Professor Brooks upon the present generation 
of American zoologists was of such notable character that the 
presentation of a ''Festschrift" by his pupils would have been a 
most natural and fitting act, and one that would undoubtedly 
have been consummated within the next few years, had not his 
untimely death prevented. Professor Brooks took so warm an 
interest in the activities of his former pupils, that it is certain he 
would have been deeply gratified to receive a tribute of this kind, 
and it is a source of much regret on the part of those who have 
helped to bring forth the present volume, that it was not issued 
during his lifetime. It seems none the less appropriate, however, 
to publish the volume as a memorial, and hence what otherwise 
might have i een done amidst gladness and felicitation is now 
done with a sense of affectionate remembrance and regard. 
Plans to this end were proposed shortly after Professor Brooks' 
death, at a meeting of his pupils and associates held in Baltimore 
on December 31, 1908. It was at that time suggested to issue 
a special volume of the Journal of Experimental Zoology in 
commemoration of his life and work. Brooks' direct activities 
lay mainly in the field of comparative and philosophical mor- 
phology, and hardly extended into that of experimental zoology 
as now understood. But a man's work may bear as abundant 
fruit in that of his pupils and followers as in his own immediate 
achievement. Some of those who have in later years devoted 
themselves to experimental studies, have borne witness to his 
awakening of their interest in these problems, and to his clear 
recognition of experiment as a first necessity of biological prog- 
ress. The Editorial Board of the Journal of Experimental 
Zoology, of which he was a member from its organization, there- 
fore gave cordial assent to the use of its pages for the purpose 
that has been indicated and a committee to carry out the pro- 
