PREFACE 



THE following monograph embodies the first of a series of 

 lectures on Physiology, delivered by the Physiologists of 

 London in the Laboratory of their University. 



The general object of the scheme of which these particular 

 lectures form part, is to present the results of recent investiga- 

 tion by the investigators themselves orally and with experi- 

 mental demonstration in the lecture-room outside the lecture- 

 room by monographs approved by the University. 



With the modification considered suitable for the case of 

 University publications, the procedure of the Royal Society as 

 regards the printing of papers in the Philosophical Transactions 

 has been adopted by the Senate of the University of London, 

 the regulations in connection with the official publication of 

 lectures being as follows : 



" Manuscripts of Lectures delivered, or of the results of investiga- 

 " tions made in the Physiological Laboratory of the University, shall, 

 " in first instance, be submitted for consideration to the Physiology 

 " Committee, to be referred, if considered suitable, to two referees, who 

 " shall be requested to report to the Physiology Committee as to their 

 " fitness for publication. 



" Manuscripts shall be accepted only if reported suitable for publi- 



" cation 



" A. By reason of additions to knowledge in Physiology and 

 " Experimental Psychology. 



" B. By reason of excellence of exposition of recent additions to 

 " knowledge and doctrine in Physiology and Experimental 

 " Psychology." 



The present eight lectures embody in large measure the 

 recently published (and unpublished) results of my own current 



