viii PREFACE. 



laid deep, as all the thinking world knows, in this 

 department of science. 



Even those who may find fault with the super- 

 structure, cannot deny the reality of its deep foun- 

 dations. 



A few words about the origin of this little work 

 will explain and apologize for certain personal allu- 

 sions, particularly in the seventh chapter. 



Last March, a Grerman professor of chemistry 

 wrote to me from a town in Saxony, asking for an 

 "exhaustive and impartial" account of the system 

 of Mr. Joseph Wallace. This set me to try and 

 explain so far as I could (keeping carefully to the 

 outside of the system itself) the connection between 

 Wallace's discoveries and generally accepted scien- 

 tific teaching in Chemistry and Biology. 



J. H. N. NEVILL. 



The Vicarage, 



Stoke Gabriel, S. Devon. 

 January, 1890. 



