LOW TEMPERATURE — DEVELOPMENT OF FUNDULUS 475 



direct chemical action, sucli as precipitation or decomposition, 

 and which can also produce disturbances in the arrangement of 

 nuclear and cytoplasmic substances that are actually visible, 

 hut ^^hich may only be assumed to have destroyed any chemi- 

 cally and developmentally differentiated and specifically neces- 

 sarj^ materials. In this respect my experiments afford, I think, 

 a \'aluable check on the results following chemical treatment 

 and indicate the more general validity of the disorganization 

 hypothesis. 



And further, since I have observed several instances where 

 eggs exhibiting rather extensive fragmentation and dispersal of 

 protoplasmic parts, were still able to form normal embryos, I am 

 led to believe that such conditions in themselves need not lead 

 to abnormal development, but that some other condition must 

 be primarily responsible. If certain essential organizational 

 conditions may remain present or susceptible of restoration, 

 development may proceed normally even though some consider- 

 able parts of the egg protoplasm may actually have been de- 

 stroyed; a conclusion which is also indicated by the results of 

 removal and pricking experiments on single blastomeres of the 

 Teleost ovum (Morgan '93). 



Most of Werber's discussion of the action of his mode of 

 treatment centers about the actual mode of the production of 

 eye-defects and of the respective merits of the 'fusion' and the 

 'inhibition' hypotheses. But such a discussion sieems concerned 

 rather with the after effects than with the real causes of the 

 abnormality. That is, while it is very important to know the 

 proximate causes of such a condition as cyclopia, neither of the 

 suggested causes is really fundamental, and either fusion or 

 inhibition may result from a primary organizational disturbance, 

 in the same way that varieties of nutritional abnormality may 

 also result from a similar underlying cause. 



In one respect Werber seems to fall into the error made by 

 Stockard in assuming that such conditions as cyclopia result 

 from a specific effect upon a differentiated rudiment of the an- 

 terior end of the central nervous system, already differentiated 

 in the earl}^ cleavage group. This leads him ('15, pp. 557-8) to 



