470 WM. E. KELLICOTT 



The difficulty of explaining such an abnormahty as monoph- 

 thalmia asymnietrica; or other asymmetrical abnormalities, on 

 this nutritional basis is also apparent. Stockard recognizes this 

 and merely suggests that "It might be that at some critical 

 point in development one of the future eye centers is affected 

 after the growth centers had begun to localize in more or less 

 lateral positions" ('13 b, p. 278). Such asymmetrical abnor- 

 malities offer no special difficulties of interpretation on the 

 disorganizational hypothesis. 



Stockard ('13 b, p. 281) has also noted that the earlier the 

 treatment is administered during the development of Amblys- 

 toma the more extensive are the resulting abnormalities: "the 

 developmental period of administration is of as high importance 

 in determining the result as is the nature of the stimulus used." 

 This is readily understood upon the hypothesis that the unusual 

 stimuli act by disturbing the normal organizational relations of 

 nucleus and cytoplasm, since a simple or localized disturbance 

 at an early stage would be followed by much more widespread 

 effects than would an equal disturbance at a later stage, when 

 many of the differentiations might be already determined and 

 the effects consequently more localized. After the essential dif- 

 ferentiations of the organism have been made, the effects of 

 external stimuH would be Hkely to have relatively shght mor- 

 phogenetic results. (Compare the morphogenetic results of 

 stimulation in embryo and in adult organisms.) 



Stockard beheves that "all of the eye conditions [in Fundulus] 

 may be interpreted as arising through developmental arrests 

 ('13 a, p. 83); and throughout his papers the abnormahties ob- 

 served are continually referred to as 'defects,' an interpreta- 

 tion that is cited in support of the nutrition hypothesis. While 

 most of the abnormahties observed have the nature of defects, 

 if bA^ defect we mean only failure to differentiate, yet not all of 

 the abnormahties noted in Fundulus, to mention but this case, 

 are of this nature. In my own observations I might mention 

 for example, the development of two complete and separate 

 embryos on a single yolk; the development of two separate 

 hearts, not paired but in different regions of the embryo; the 



