WHAT OF IT? AN OPEN LETTER TO STUDENTS 523 



Persons, S. (ed.). Evolutionary Thought in America. New Haven: Yale Uni- 

 versity Press, 1950. 



Simpson, G. G. The Meaning of Evohition. New Haven: Yale University Press, 

 1949. 



Sullivan, J. W. N. The Limitations of Science. New York: Viking Press, 1933. 

 Also Mentor Book MD35, New American Library, New York. 



