viii TYPE OR COMMON PLAN 103 



As time went on, however, and men began to obtain a 

 deeper insight into these subjects, resemblances either between 

 the whole structure or between particular parts of different 

 animals, which could not be explained on the utilitarian 

 principle, became strikingly obvious. Moreover, such things 

 as rudimentary and functionless organs in one animal, repre- 

 senting developed or functional organs in another, became 

 known in the further prosecution of morphology. Then the 

 idea gradually dawned that there was some " secret bond " 

 which linked creature to creature, and which permitted 

 deviation only to a certain point from a certain given pattern 

 of construction. 



This was the doctrine of type or common plan. A " type " 

 or a " common plan " for each natural group of the animal 

 kingdom was supposed to have influenced, or to have been 

 held in view at, the creation of every different species com- 

 posing that group, the deviations from this type being related 

 to the special exigencies of the particular species. 



This was a great step in advance when regarded as a mere 

 exposition of the facts of morphology, and when the idea was 

 not carried out by fanciful imaginations beyond the point 

 warranted by these facts. Upon this view many anatomists of 

 great eminence seemed to rest. But still it explained nothing, 

 accounted for nothing. It gave not even a shadow of a reason 

 for the resemblances amid diversity found everywhere. It 

 only asserted that the Creator had imposed certain apparently 

 quite arbitrary restrictions to His power; but, beyond this 

 almost paradoxical assertion, it gave no clue to elucidate any- 

 thing like a theory of creation. 



In the meanwhile, however, the great results arrived at in 

 other branches of science, the increasing accumulation of facts 

 from various sources, all tending to show that the orderly and 

 harmonious working of the whole universe was due to con- 

 stantly acting causes or laws, acting now, having acted for 

 immeasurable time past, and, as far as we can see, about to 

 act for immeasurable time to come, the great work of the 

 astronomers and the geologists, leading to " the general con- 

 ception of some great principle of orderly evolution, according to 

 which the present as well as past systems of existence have 



