ORIGIN OF MONSTERS. II 433 



have apparently sustained no destruction due to this or any other 

 factor. The symmetry in anatomical details observed in 'Cos- 

 mobia' may, I venture to say, be only an incident — symmetrical 

 blastotomy and the subsequent undisturbed development of 

 the primordia which havej thus incidentally, remained equipo- 

 tent. Conversely we may assume that where (osmotic) 

 blastotomy or blastolysis (both osmotic and chemical) causes 

 destruction of some areas of the germ, any monster and — if the 

 germ has also been split into two more or less equivalent parts — 

 any deformed duplicity may result from further development. 

 The distinction between these two kinds of duplicities is, 

 accordingly, mainly one of degree; it is a quantitative differ- 

 ence rather than a qualitative one and it may depend upon the 

 specific action (either chemical or physical or both chemical 

 and physical) of the (probably chemical) agent primarily respon- 

 sible for the deviation from the typical course of development. 



Moreover, this quantitative difference may, as pointed out 

 above, depend also upon the 'age' of the egg, the 'younger' 

 eggs being hardier and more capable of surviving blastotomy 

 without sustaining fatal lesions, while the 'older' ones with a 

 tendency to cytolytic fragmentation may apparently be (in a 

 varying degree) more subject to such lesions produced by blas- 

 totomy or blastolysis. 



The 'old age' of the egg is, undoubtedly, a germinal variation, 

 but this 'variation' is in the nature of a pathological change and 

 the causes underlying the latter may well be within the bounds 

 of discovery, as is suggested by the recent researches of Gold- 

 farb (I.e.). The germinal variation, however, assumed by 

 Wilder is not a pathological condition and being nothing else 

 that could intelligibly be defined, it automatically puts a stop 

 to further inquiry into the primary causes underlying diplo- 

 genesis in nature. 



While I am not at all inclined to underestimate the almost 

 insuperable difficulties presented by the problem, I cannot on 

 the other hand subscribe to Wilder's skepticism voiced in the 

 following characteristic remark ('08, p. 428) : 



