THE EVOLUTION OF ANIMAL FUNCTION 473 



matter of their science. Of course it will be urged that the 

 quarrel over the use of functional characters in classification 

 took place a century ago, and is long ago forgotten ; that no 

 biologist now takes seriously or even remembers the arguments 

 by which Geoffroy St. Hilaire established the monopoly of 

 morphology. All this may be conceded. Nevertheless I would 

 maintain that in the divorce of evolution and physiology there 

 is something more than the mere preoccupation of physiology 

 with the pressing claims of medicine. 



It is not implied that physiologists are at this present day 

 directly prevented from developing their science on comparative 

 lines by any views that may now be held as to the value of 

 functional characters as a test of animal relationship. The point 

 is rather that the original exclusion of functional characters 

 from the criteria of classification robbed physiology of that 

 compelling stimulus which has made morphology a comparative 

 science. When the failure of physiology to take any part in 

 animal classification or in the determination of genetic relation- 

 ship is attributed to the preoccupation of physiologists with 

 more immediate problems, it is implied that the old quarrel 

 between structural and functional characters played no part in 

 the matter. But in such a view of the case there is in all 

 probability a confusion of cause and effect. It may well be 

 maintained that the preoccupation of physiology with the study 

 of man, and its failure to develop on comparative lines, were 

 simply the outcome of its exclusion from the problem of animal 

 classification. 



It will be of interest to attempt at this stage to recall the 

 history of those events which resulted in the exclusion of 

 functional characters from the determining of animal relation- 

 ship. For if no other purpose be served, we may at the least 

 hope to see how widely the modern conceptions of function differ 

 from those which were held in the time of Cuvier. And so 

 we may be led to a clearer formulation of the problems which 

 now await solution from the comparative study of function. 



It was about the middle of the eighteenth century that the 

 organisation of animals began to be treated on a definitely 

 and consciously comparative basis. Such men as Daubenton 

 in Paris and John Hunter in London set before them, as the 

 object of their study, the comparison of animals one with 

 another. And naturally enough they took as the matter of 



3i 



