SUGGESTED READINGS 311 



photographs of gastrulation, and a comparison of chick and amphibian 

 gastrula. 



Needham, J., Biochemistry and Morphogenesis. Describes amphibian 

 development, gastrulation, mapping of presumptive values, mechanism of 

 gastrulation, etc. 



Huettner, A. F., Fundamentals of Comparative Embryology of the 

 Vertebrates. Presents excellent three-dimensional figures of the blastula and 

 gastrula. An invaluable aid to visualizing the internal changes during gas- 

 trulation. 



McEwen, R. S., A Textbook of Vertebrate Embryology. Contains a com- 

 parison of chick primitive streak with amphibian blastoporal lips. ' 



Chapters 6 and 7 



A number of penetrating analyses of embryonic induction are available. 

 Here is a partial list: 



Spemann, H., Embryonic Development and Induction, Yale University 

 Press, 1938. Clear, concise exposition of the experiments. 



Needham, J., Biochemistry and Morphogenesis. Analytical, biochemical 

 treatment of the organizer. The organizer is treated as a compound released 

 by induction. 



Child, C. M., Problems and Patterns of Development. Organizers in 

 various species. The gradient concept in relation to the organizer. 



Huxley, J. S., and de Beer, G.R., Elements of Experimental Embryology. 

 A well-illustrated treatment of the experiments described in the text. 



Weiss, Paul, Principles of Development. Analytical treatment of the 

 organizer problems and potencies. 



Chapter 8 



Huxley, J. S., and de Beer, G. R., Elements of Experimental Embry- 

 ology. A very complete discussion of the field and a well-illustrated survey 

 of experiments. 



Weiss, Paul, Principles of Development. An analysis of the field concept. 



Child, C M., Problems and Patterns of Development. The field as a 

 quantitative gradient. 



