92 



held by Wallace and the " Neo-Darwinians " as practically the 

 only source of evolutionary changes, is held by Professor de Vries 

 to have no effect whatever in giving rise to new specific and 

 varietal distinctions, though it is of great importance both in 

 nature and in culture, in that it allows a certain amount of adap- 

 tive change or amelioration within the species. 



The editor professes to have changed as little as possible the 

 original diction of the author, and for this the reader will be 

 grateful both because it leaves unmodified the simple, genial flavor 

 of the author's personality and because no material change is 

 conceivable which would not have resulted in a more involved 

 style. Some changes might have been introduced, however, 

 w^hich would have been distinct improvements, and it is to be 

 hoped that in succeeding editions these changes will be made. 

 Thus the description of the zygomorphic or bilateral flowers of 

 Digitalis as "symmetrical" is using in an unusual though liter- 

 ally correct sense a word that has long been in use in descriptive 

 botany with a totally different meaning. Another even less' de- 

 sirable practice of quite similar character is the interchangeable 

 use of "retrogression" and "regression" for the mutative loss 

 of a character. " Retrogression " was the term first applied by 

 the author to this process and there is no reason why it should 

 not be used exclusively in biological terminology in this very 

 definite sense. " Regression " already has a distinctive signifi- 

 cance in connection with " fluctuation " and is used in its proper 

 sense in Section F. which is devoted to that subject. Much con- 

 fusion will be avoided if in future editions " retrogression " be 

 substituted for " regression " wherever the mutative loss of a 

 character is intended. An added complication in this connection 

 is found on page 221, where, presumably by a typographical 

 error, " degressive evolution" is rendered " regressive evolution." 

 A number of other typographical errors occur, but in most cases 

 the context prevents misinterpretation. Aside from these the 

 press-work leaves little to be desired. 



The year 1904 will always be memorable in the annals of 

 American science because of the number of distinguished foreign 

 scientists who visited this country during that summer. Of these 



