ORIGIN OF MONSTERS 523 



Very recently Mall ('08) and Whitehead ('09) have advanced 

 essentially identical \dews in confirmation of Lewis' ('09) con- 

 clusions. 



Thus, as we see, the recent authors practically all agree upon 

 the mode of formation of the 'cyclopean' eye. However, the 

 fusion theory of 'cyclopia' does not altogether lack opponents, 

 as the most ardent of whom we must now regard Stockard. 



For a critique of this author's views the reader must be re- 

 ferred to Spemann's ('12 a and b) excellent discussion. While 

 on the basis of evidence in my possession much could be added 

 to the latter, I shall for the present confine myself largely to the 

 discussion of the arguments which Stockard has most recently 

 ('13) brought forth in defense of his ^dews on the morphogenesis 

 of 'cyclopia.' 



Concluding from his experiments with magnesium chloride on 

 Fundulus eggs and also from experiments with alcohol, ether, 

 and chloroform-acetone solutions on the same material and with 

 very similar results, Stockard ('09, '10a, p. 387) concluded that 

 ''the evidence strongly indicates that the ophthalmic abnormal- 

 ities produced in these experiments are the result of an anaes- 

 thetic action during the early developmental stages." 



The fallacy of this h^^Dothesis of anaesthetic inhibition has 

 become obvious since the work of McClendon who has recently 

 ('12 a) shown that 'cj^clopia' and other malformations of the 

 eye can be produced by various other, non-anaesthetic sub- 

 stances. Thus in his most recent pubhcation, Stockard ('13) 

 no longer speaks of 'anaesthetic^ action,' but instead he con- 

 siders his experimental eye terata as "the result of a weakened^ 

 development" which is brought about by the toxic solutions. 

 These solutions, he argues, "all tend to suppress or arrest the 

 development of the eye material in the brain." ('13, p. 271). 



Stockard ('13, p. 254) believes 



that the eye anlage in the medullary plate is primarily median and 

 single and normally separates into two almost equal growth regions, 

 which develop in lateral directions reaching further and further out 



* Mv own italics. ' 



