8 The Science of Life. 



this is not the full statement, for the species-maker of 

 to-day has in most cases a conception of species very 

 different from that of Linnaeus, and the so-called modern 

 Cuvierian is now, in most cases, aware that he is de- 

 ciphering the structural record of genetic affinities. 

 The evolution doctrine has altered the tone of work at 

 all the levels of analysis; and what is true of this 

 greatest generalization is true of some of the minor ones 

 as well. 



It would be interesting to define precisely what are the 

 characteristics of modern work in the different depart- 

 After ments of biology. But the task is a very 

 Darwin, difficult one. Since Darwin began to sway 

 the minds of biologists there have been many changes, 

 some of them directly, others indirectly, due to his 

 influence. It is probable that the main currents of pro- 

 gress will be clearer a hundred years hence than they 

 are to those within their sweep, and it may be that 

 some ideas which now appear of doubtful survival 

 value will afterwards become of paramount importance. 

 As the result of evolutionary views, classification has 

 tended to become a record of pedigrees. Not that the 

 pre-Darwinian classifiers failed to look for, or to find, 

 natural affinities, but the doctrine of descent has invested 

 these with new meaning. We may associate the change 

 with the name of Haeckel, who championed genealogi- 

 cal trees in the days of early unpopularity. 



The change in morphological work may perhaps be 

 generally expressed by saying that it has acquired an 

 evolutionary purpose. A piece of " pure anatomy" may 

 be part of a necessary discipline, and it is always pos- 

 sible that it may fill a vacant niche ; on the other hand, 

 its value may be altogether quantitative. A perception 

 of this has tended to favour work which imitates Gegen- 

 baur's rather than that which remains Cuvierian. As 

 Prof. E. Ray Lankester says, " Pure morphography 

 has long since ceased to be a principal line of research ". 

 In the domain of histology, the most striking feature 

 has been the concentration of research on the problems 

 of cell-division (E. van Beneden, Boveri, O. Butschli, 

 W. Flemming, O. and R. Hertwig, and many others). 



