LAUGEL'S PROBLEMS OF NATURE AND LIFE. 347 



merits to be brought thus far before our readers, both 

 from its intrinsic plausibility and as an example of the 

 great questions which are now currently discussed in 

 the scientific world. 



The third of M. Laugel's volumes comes before us 

 entitled 'Problemes de la Vie.' a title expressing at 

 once the mysteries of the subject, and, to those who 

 have read his preceding volumes, the line of thought 

 and argument he is likely to pursue in dealing with 

 them. Leaning towards materialism, yet not in the 

 same hard and exclusive sense as Virchow, Vogt, and 

 other German writers, he seeks, as far as possible, to bring 

 vital functions within the domain of ordinary physics ; 

 and argues, as others have done, against the use or 

 abuse of those terms, ' vital principle,' 'vital force,' ' vital 

 energy,' which have been employed to veil our igno- 

 rance of the reality. Eefraining from analysis, or any 

 general adoption of his opinions, we think it better to 

 present to our readers a summary view (in sequel to 

 an article many years ago) of what science and specula- 

 tion are still doing in this ample field of enquiry. 



The first of the ' Problems of Life ' lies in the 

 question ' What is Life ? ' It has undergone a dozen 

 definitions ; some by eminent authorities, but all liable 

 more or less to objections from error, incompleteness, 

 or obscurity. The problem has pressed upon every 

 age of mankind, and in our own time has been brought 

 into connexion with the latest discoveries of physical 

 science. Still, however, we need a definition which 

 may satisfy all the conditions without becoming value- 

 less from its generality. That given us by Aristotle, 



