So CHAPTERS ON EVOLUTION. 



V. 



THE EVIDENCE FROM RUDIMENTARY 

 ORGANS. 



IN the exercise of his scientific attainments, there is one aspect 

 in which the naturalist of to-day bears a certain likeness to the 

 detective officer. The latter is perpetually endeavouring to " strike 

 the trail >; of the offender through his dexterity in the discovery of 

 clues to the movements of the pursued, and attains his end- most 

 surely and speedily when the traces he has selected are of trustworthy 

 kind. The naturalist, on his part, has frequently to follow the history 

 of an animal or plant, or it may be that of a single organ or part in 

 either, through a literal maze of difficulties and possibilities. His 

 search after the relationship of an animal may be fraught with as 

 great difficulty as that which attends the discovery of a "missing 

 heir " or lost relative in actual life ; and his success in his mission 

 is found to depend, as does that of the detective's work, simply on 

 the excellence and trustworthiness of the clues he possesses, and on 

 the judicious use to which he puts his "information received." It 

 cannot be denied, however, that modern aspects of science and 

 present-day tendencies in research have largely increased the resem- 

 blance between the enforced duties of the criminal investigator and the 

 self-imposed task of the biologist. When, formerly, the order of 

 nature was regarded as being of unaltering kind and of stable consti- 

 tution; naturalists regarded animals and plants simply as they existed. 

 There was of old no looking into the questions of biology in the light 

 of "what might have been;" because the day was not yet when 

 change and evolution were regarded as representing the true order 

 of the world. When, however, the idea that the universe both of 

 living and non-living matter had an ordered past dawned upon the 

 minds of scientists, the necessity for tracing that past was forced 

 upon them as a bounden duty. With no written history to guide 

 them, the .scientific searchers were forced to read the " sermons in 

 stones" which nature had delivered ages ago. Without clear and 

 unmistaken records to point the way, they had to seek for clues and 

 traces to nature's meaning in the structure and development of 

 animals and plants; and, as frequently happens in commonplace 

 history, the earnest searcher often found a helping hand where he 

 least thought it might appear, and frequently discovered an important 

 clue in a circumstance or object of the most unlikely kind. 



