PSYCHE. 



[July— August i88S. 



differences and in this way try *d ex- 

 plain why they differ from each other 

 and why some kinds exist instead of 

 others that might have existed. 



The study of microscopic anatomy 

 attempts the same thing with smaller 

 objects. It compares cells together and 

 classifies them into layers and tissues 

 and so tries to explain the cause of their 

 differences and why they combine to- 

 gether some into one organ and some 

 into another. 



In the stud}- of species there is use 

 for all the facts that can be found. It 

 is true our classifications of most 

 animals is based on a very superficial 

 knowledge of them but this is because 

 the number of animals is so great that 

 there has not been time to know more. 

 There is no prospect of everything being 

 known about any one animnl and our 

 classifications and theories must be 

 made to suit the facts as they are and 

 then improved as knowledge increases. 



It has often been urged against the 

 study of species that is largely a study 

 of names, and students have turned to 

 histology or embryology hoping to 

 avoid this and accomplish more with 

 the same labor. This may have been 

 possible once but any embryological 

 or histological book of the present time 

 has as large a part devoted to the 

 meanings of words and interpretations 

 of the descriptions of other writers on 

 the same subject as any book on classi- 

 fication, nor is there any reason to 

 believe that the proportion of space 

 thus devoted to synonymy will decrease- 



The classification of species is largely 



based on specimens which are kept in 

 museums more or less public and it is 

 often possible for persons interested to 

 compare them with what has been 

 written about them and the importance 

 of preserving such type specimens is 

 generally recognized. 



The type specimens of microscopic 

 studies are generally kept by individual 

 students and are small and easily de- 

 stroyed so that the facilities for com- 

 parison are small. 



Thus the mistakes of systematic natu- 

 ral history are more easily seen and the 

 difference between good and bad work 

 undeistood by a large number of 

 persons while the mistakes of micro- 

 scopic observations are hard to find and 

 so supposed to be rare. 



The students of the present day can 

 therefore go on describing new cells 

 with the same freedom v\'ith which 

 those of the past generation described 

 species leaving to those that come after 

 them to correct and explain whiit they 

 have written. With increase in the 

 number of students this advantage is 

 passing away and the histologist will 

 soon have to spend as much labor in 

 identifying what he finds as the student 

 of species. 



When the attractions of a new study 

 are gone we shall see that, except in 

 the size of the object studied these two 

 lines of w'ork differ but little and one is 

 as likely to gather valuable facts and 

 new theories as the other and thai in 

 either field the value of the work 

 depends only on the care and skill with 

 which it is done. 



