Mast, Orientation in Euglena with some Remarks on Tropisms. lil>,'> 



the process there is nothing in the writings of either Jennings 

 on myself that in any way opposes his theory. As a matter of 

 fact our work has no direct bearing on this question. 



But the most surprising statement I have yet seen is that 

 found in the quotation given above, in which Ewald implies that 

 it was necessary to refute our conclusions in order to put the study 

 of behavior on an experimental basis. Is it really possible for 

 anyone at all familiar with the searching and ingenious experimental 

 work of Jennings on behavior to hold such an opinion! 



Literature cited. 



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in Euglena. Jour. Exp. Zool., Vol. 15, pp. 383428. 

 Cand olle, A. P. cle, 1832. Physiologic vegetal. A German translation by Roper, 



pub. in 1835. 



Darwin, Charles and Francis, 1880. Power of Movement in Plants London. 



592 pp. 



Davenport, C. B., 1897. Experimental Morphology. Vol. 1. New York. 280pp. 

 Engelmann, T. W., 1882. fiber Licht- und Farbenperzeption uiederster Orga- 



nismen. Arch. f. d. ges. Physiol., Bd. 29, pp. 387400. 



1883. Bacterium Photometricum. Ibid.. Bd. 30, pp. 95124. 

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Loeb, J., 1906. The Dynamics of Living Matter. New York. 233 pp. 



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1912. The Mechanistic Conception of Life. Chicago. 232 pp. 

 and Ewald, W. F., 1914. Uber die Giiltigkeit des Bunseu -Roscoe'schen 

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Mast, S. O., 1907. Light Reactions in Lower Organisms. II. Volvox, Jour. 

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1911. Light and the Behavior of Organisms. New York. 410 pp. 



1912. Behavior of Fire-Flies (Photinus Pyralis)? with Special Reference to 

 the Problem of Orientation. Jour. An. Behav., Vol. 2, pp. 256272. 



Parker, G. H., 1914. Experimentalism in Zoology. Science, N. S., Vol. 39, 



pp. 381-385. 

 Sachs, J. v., 1887. The Physiology of Plants. Trans, by H. M. Ward Oxford. 



836 pp. Original edition, 1882. 

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and Hays, Grace P., 1914. The Role of Random Movements in the 

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