PREFATORY NOTE. vii 



strange that experienced and acute biologists 1 should so far 

 misunderstand the spirit and language of cytological research 

 as to imagine that any one expects to explain life and get rid 

 of its mysteries " by imagining a living creature indefinitely 

 divided into minute living parts." Some place the secret of 

 life in the cell, others in smaller units ; but no one, so far as I 

 know, has looked upon the unit as anything more than the seat 

 of the mystery. 



Just as the final proofs of these lectures reached us, came the 

 lamentable news of the decease of one of the authors of these 

 lectures, our colleague, Professor John A. Ryder of the Uni- 

 versity of Pennsylvania. Absence of data prevents a full 

 statement. 



American biology thus loses one of its ablest representatives, 

 and the Marine Biological Laboratory one of its most valued 

 friends. Those who are familiar with Dr. Ryder's contribu- 

 tions to animal morphology and to the biological questions of 

 the day, and especially those who by close acquaintance came 

 to see the whole-souled integrity of the man, the depth of his 

 loyalty, and the purity of his honor, will deeply deplore his re- 

 moval and mourn the loss of his genial and inspiring presence. 



C. O. WHITMAN. 

 1 Mivart. Harper's New Monthly Magazine, March, 1895. 



