EVOLUTION 1091 



two or three evenings. Some of them never see full daylight ; and in 

 Lucerne, like the moths to the candle, they are "drawn" to the 

 lamps in myriads. This obligatory movement or tropism does not 

 concern us at present. The mayflies' wedding dance becomes in 

 lamplight a dance of death ; and for 30 or 40 feet underneath one of 

 the Lucerne lamps the ground was covered one or two inches deep 

 with their delicately beautiful bodies. But what can we say save 

 that a way of life which is effective for the race in natural conditions 

 may be dismally inappropriate in artificial circumstances? During 

 the ages when these old-fashioned insects were being evolved there 

 were no brilliant lights to be guarded against. Nature must be 

 acquitted. 



Passing to a higher level, Prof. Ritter gives examples, familiar to 

 most of us, of the distracted way in which birds often hurt them- 

 selves in trying to escape from a room. They fly in through the 

 widely open lower half of the window; they find themselves in a 

 very strange environment; they are torn by confused impulses — 

 including a desire to escape from their would-be friends — and they 

 dash themselves to death against the upper pane. Since even a 

 clever man may walk up against a partition of plate glass, we cannot 

 profess to be much concerned with the bird's imperfection. We can 

 balance against it the way in which a bat, entering the room, will 

 fly under a chair without knocking against anything, and will 

 re-discover the window by which it entered in the darkness. As to 

 the blackbird's savage fight with its own reflection, we must remem- 

 ber what a puzzling thing a mirror must be. Even the big-brained 

 chimpanzee in Kohler's experiments tried persistently to grab the 

 grimacing fellow on the other side of the looking-glass. We have 

 watched a fox-terrier, belonging to a highly intelligent race, fighting 

 furiously and for a long time with his reflection in a shallow trough 

 of water, and getting well soused in the process. 



Ritter maintains that birds contribute to their own undoing by 

 the imperfection of their adaptations. The resplendent 0-0 (Moho 

 nobilis) of the Hawaiian Islands calls attention to its presence by 

 its often repeated loud call. The Hawaiian barnacle-goose has become 

 a terrestrial bird, and it is now courting destruction by rigidly 

 returning to the same breeding places year after year. This is the 

 more disastrous because when the goslings are being led around by 

 their parents the former cannot fly because they are too young, 

 and the parents cannot fly because they are moulting. Not many 

 years ago the Passenger Pigeon seemed to have a stronghold in 

 North America. It occurred in such multitudes that their flights 

 eclipsed the sun and the air smelt of pigeon for miles and for days. 

 But there came an extraordinarily sudden check to its numbers 

 and prosperity; in a short time the Passenger Pigeon became an 

 extinct species. The reasons for this are far from being clear, but 



