THE EVOLUTION THEOKY 125 



It would be difficult to imagine an organization better 

 adapted to their mode of life than this enormous sieve. Yet 

 embryology tells us that the whales were not always furnished 

 with baleen, but that they developed by gradual adaptation from 

 dolphin-like ancestors possessing teeth. This fact was already 

 known to St.-Hilaire, one of the pioneers of the Evolution 

 Theory. Recently the development of the baleen whales has 

 been thoroughly studied by Kiikenthal, upon whose drawings our 

 illustration is based. According to him the embryos develop 

 early both in the upper and under jaw complete rows of teeth, 

 but these teeth become degenerate before birth without having 

 functionated (fig. 35). 



We may even affirm that the ancestors of the mammals had 

 a regular change of teeth ; for. behind this first row of teeth, the 

 milk teeth, stands a second which also remains rudimentary. 

 Similar conditions are observed in the tortoises, whose toothless 

 jaws are armed with sharp horn-plates similar to the bill of a 

 bird ; their embryos, however, possess degenerate teeth. 



It is these rudimentary organs which no longer reach the 

 functional stage that are of utmost importance to the Evolu- 

 tion Theory. Or is there any other logical explanation of the 

 presence of rudimentary organs than that these now useless 

 formations once discharged certain useful functions in the 

 ancestors ? Is there a stronger argument against a divine 

 creative act in the Biblical sense ? Is it not an impossible con- 

 ception that an omnipotent God had created his creatures thus 

 imperfectly? But the Evolution Theory solves this problem 

 without difficulty. We know that climatic conditions on this 

 planet, air pressure, and the moisture in the atmosphere, have in 

 the course of the earth-periods undergone many changes. Where 

 to-day the land stands there the oceans roared in ages long ago ; 

 vast stretches of water have been replaced by continents. As 

 the gills of the amphibians and the swim-bladders of the 

 fishes lose or change their functions when the aquatic life is 

 exchanged for a life on land, so all other organs change with a 

 change in the conditions to which they were adapted. We have 

 seen that all organs which fall into disuse become degenerate 

 until at last they disappear altogether. As a result of the con- 

 servative element which is present in each organism and finds 



