The Dying Huanaco. 327 



coming home to be relieved from his sufferings, but 

 the motive is the same in both cases ; at the gate 

 the only pain the animal has ever experienced has 

 invariably begun, and there it has ended, and when 

 the spur of some new pain afflicts him new and yet 

 like the old it is to the well-remembered hated 

 gate that it urges him. 



To return to the huanaco. After tracing the 

 dying instinct back to its hypothetical origin 

 namely, a habit acquired by the animal in some 

 past period of seeking refuge from some kind of pain 

 and danger at a certain spot, it is only natural to 

 speculate a little further as to the nature of that 

 danger and of the conditions the animal existed in. 



If the huanaco is as old on the earth as its 

 antique generalized form have led naturalists to 

 suppose, we can well believe that it has survived 

 not only a great many lost mammalian types, but 

 many changes in the conditions of its life. Let us 

 then imagine that at some remote period a change 

 took place in the climate of Patagonia, and that it 

 became colder and colder, owing to some cause af- 

 fecting only that portion of the antarctic region ; 

 such a cause, for instance, as a great accumulation 

 of icebergs on the northern shores of the antarctic 

 continent, extending century by century until a large 

 portion of the now open sea became blocked up with 

 solid ice. If the change was gradual and the snow 

 became deeper each winter and lasted longer, an 

 intelligent, gregarious, and exceedingly hardy and 

 active animal like the huanaco, able to exist on the 

 driest woody fibres, would stand the best chance of 

 maintaining its existence in such altered conditions, 



