AUTHOR'S PREFACE 



There is, so far as I know, no work in English which aims at 

 giving an account of the physiology of the lower organisms. 

 Few of those who are aware of the existence of Winterstein's 

 monumental work are likely to find the time to obtain from its 

 encyclopaedic pages a bird's-eye view of the ground already 

 traversed and the fields that lie ripe for the research worker 

 armed with sufficient familiarity with animal life and under- 

 standing of physiological methods of inquiry. Winterstein's 

 Vergleichende Physiologic meets the needs of the research worker 

 who is in search not of problems to tackle so much as detailed 

 information of previous inquiries on similar lines to those 

 with which he is concerned. There seems nothing to supply 

 any encouragement to those who are not sufficiently advanced 

 in their studies to distinguish between lines of inquiry that are 

 practicable as well as profitable, to realise as yet what materials 

 are available for the solution of the problem in which interest 

 has already been quickened, or to have gained much insight 

 into the methods at our disposal for extending our knowledge 

 of the physiology of the lower organisms. 



I am well aware that to attempt to supply this need within 

 the limits of space at my disposal would be a sufficiently 

 embarrassing task for an author reassured with a far more 

 exalted sense of his own equipment for the task than I can 

 boast. If I have succeeded in stimulating twenty-one years of 

 age (or thereabouts) to dip into an immense and at present 

 scattered literature and find some fruitful fields of inquiry and 

 sources from which more precise information can be obtained, 

 I shall have accomplished precisely what I set out to do. 



These chapters represent the materials of a course of 

 lectures delivered first in the Zoology Department and later in 



