CYCLOPIA CAUSATION, ETC. 45 



other abnormalities which are also capable of being produced by the action of external factors, and 

 do not depend directly on atavism. The remarkably perfect and symmetrical nature of the 

 anatomical adjustments that is sometimes found both in the eye itself and in the surrounding parts, 

 seems to point to this conclusion. According to the view already expressed (pp. ix-x), the fact that 

 cyclopia may be produced by environmental factors, is rather an argument for, and not against, the 

 probability that it may also arise by abrupt spontaneous variation. 



