PREFACE. XXV 



hand too late for incorporation in their proper phiccs, new 

 publications, and a few which had been accidentally misplaced. 



The Index which closes the volume requires but little ex- 

 planation. Carrying out my firm conviction that several 

 indexes in the same book are vexatious and unprofitable, I have 

 combined all matters requiring indexing into one alphabet. 

 The 3^ears of birth and death of deceased writers are included 

 in parentheses when known to me ; if of birth or death only, 

 the distinctive initial is prefixed. 



I have inserted in the Corrigenda some dates which I have 

 ascertained with greater precision since the printing of the 

 titles in question ; also such press-errors as I have detected 

 during the indexing. The double mistake on page 171 origin- 

 ated accidentally at the moment of going to press, an instance 

 of the manner in which errors will creep in, in spite of the 

 exercise of the greatest care. 



The reader must be warned that initials are frequently 

 altered in the translation of Christian names, so that K = C, 

 and G=W, as explained on a previous page. The rules of the 

 Index Society as to prefixes have been adhered to ; but I am 

 by no means sure that they should not be extended or else 

 modified in such cases as De Bary, Van Tieghem ; these prepo- 

 sitions are meaningless in conjunction with a German and 

 French speaking author respectively. It was my intention to 

 refer to the Royal Society's Catalogue of Scientific Papers, in 

 the Index, but the great length of the Index itself forbade any 

 increment thereto ; it is the less to be regretted, inasmuch as 

 the Catalogue is itself alphabetically drawn up. 



There now remains only the pleasing duty of thanking my 

 very numerous friends and helpers at home and abroad. The 

 mere enumeration of their names would take up a large 



