272 ORIGIN OF AMPHIBIAN PIGMENT 



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Proc. Nat. Acad. Sci. 39:985-989. 

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Arch. f. Ent. Mech. 134:122. 

 ROSIN, S. , 1943 - "Experimente zur Entwicklungsphysiologie der Pigmentierung bei Amphibien. " Rev. Suisse de Zool. 50:485. 

 SAWYER, C. H. , 1947 - "Cholinergic stimulotion of the release of melanophore hormone by the hypophysis in the salamander. " 



Jour. Exp. Zool. 106. 

 SERRA, J. A. , 1943 - "Sur la nature des melanines et la melanogenese. " Genetica, 23-300. 



STONE, L. S. , 1932 - "Selective staining of the neural crest and its preservation for microscopic study. " Anot. Rec. 51:267. 

 STONE, L. S. , 1933 - "The development of the lateral -line sense organs in Amphibians in living and vital-stained preparations. " 



Jour. Comp. Neur. 57:507. 

 SZEPSENWOL, J. , 1945 - "The influence of the eyes on the melanophores in Amphibia. " Anat. Rec. 93:185. 

 TWITTY, V. C., 1945 - "The developmental analysis of specific pigment pattern. " Jour. Exp. Zool. 100:141. 

 TWITTY, V. C. G D. BODENSTEIN, 1944 - "The effect of temporal and regional differentials on the development of grafted 



chromatophores. " Jour. Exp. Zool. 95:213. 

 TWITTY, V. C. G M. C. NIU, 1954 - "The motivation of cell migration studied by isolation of embryonic pigment cells singly 



and in small groups in vitro. " Jour. Exp. Zool. 125:541-514. 

 WARING, H. , 1941 - "The co-ordination of vertebrate melanophore responses. " Biol. Rev. 17:120. 



WATTERSON, R. L. , 1942 - "The morphogenesis of down feathers with special reference to the developmental history of melano- 

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 WEISS, P., 1941 - "Melanin formation by deplanted fragments of thalamus in Amphibian lar\'ae. " Proc. Soc. Exp. Biol. G Med. 



48:343. 



"Man is tnetaphysical and proud. He lias gone so far as to think that 

 the idealistic creations of his mind, which correspond to his feelings, also 

 represent reality. Hence it follows tJiat the experimental method is by no 

 ineans natural to man, and that only after lengthy wanderings in theology 

 and scholasticism lias he recognized at last the sterility of such efforts . . . 

 The human mind has at different periods of its evolution passed successively 

 through feeling , reason , and experiment . First, feeling alone, imposing 

 itself on reason, created the truths of faith or theology. Reason or phil- 

 osophy, the mind's next mistress, brought to birth scholasticism . At last, 

 experiment, or the study of natural phenomena, taught man the truths of 

 the outer world are to be found ready -formulated neither in feeling nor in 

 reason. These are indispensable merely as guides: but to attain external 

 truths we must of necessity go down into the objective reality . . . .In the 

 search for truth by the experimental method, feeling always takes the lead: 

 it begets the a priori idea or intuition; reason or reasoning develops the 

 idea and deduces its logical consequences. Bid if feeling must be clarified 

 by the light of reason, reason in turn must be guided by experiment. " 



Claude Bernard 



