Seasonal Changes 



Fishes kept in the dark will eventually become colourless, 

 if they survive the ordeal, as many of them will. Many 

 creatures live normally in dark caves where not a ray of 

 light ever reaches them ; such an animal is the proteus, a 

 salamander from the caves of Dalmatia. In colour it is 

 a very delicate pink in reality it is white, but its blood 

 gives it a pink hue. Now when the proteus is brought 

 into the light it gradually turns black ; moreover, such 

 specimens produce black young. 



External influences, not directly due to changes of 

 season, may, naturally, effect animal life. As proof of 

 this statement there is a familiar and easily performed 

 little experiment which anyone may try. The common 

 tadpole, as everyone knows, will, under normal conditions, 

 develop into a frog ; in doing so it loses its feathery gills 

 and abandons its purely aquatic life, becoming an air- 

 breathing creature and more or less terrestrial. If, how- 

 ever, perforated zinc or some similar material be placed 

 just below the surface of the water in which the tadpoles 

 live, in such a manner that they are prevented from coming 

 to the surface, they will retain their gills and continue to 

 grow for two or three years, growing in that time into 

 veritable tadpole giants. 



Now there is a most extraordinary relative of the frog 

 which is blessed with two names ; it is sometimes called 

 the axolotl and sometimes the amblystoma. It came 

 by its two names quite by accident, and retains them 

 more by courtesy than by right. The axolotl resembles 

 a large newt, and its home is in the North American lakes. 

 It has lungs and also breathing gills like a tadpole ; its 

 tail is large and flattened sideways. Now in the same 

 lakes and on their shores the amblystoma dwells ; devoid 

 of gills, and with a lizard-like tail, it only bears a slight 

 resemblance to the axolotl. As may be inferred, the 

 young axolotls grow into old axolotls, and the young 

 amblystomas into old amblystomas ; on the face of it, there 

 is nothing remarkable in that. But imagine the surprise 

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