318 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1951 



of their action. To discover the nature of the substrate upon which 

 they act, the integrated germ of the organism carried by the living 

 cells (12), is a problem that touches upon the nature of life itself, and 

 may well tax the ingenuity of the biochemist for some time to come. 



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9. WiGGLESWOKTH, V. B. Ibid., vol. 79, p. 91, 1936. 



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11. WiGGLESWORTH, V. B. Ibid., vol. 25, p. 1, 1948. 



12. WiGGLESWORTH, V. B. SyiBposia Soc. Exp. Biol., vol. 2, p. 1, 1948. 



13. WiGGLESWORTH, V. B. Nature, vol. 168, p. 558, 1951. 



14. Williams, C. M. Growth Symposium, vol. 12, p. 61, 1948. 



