PRE-PUBLICATION STATEMENT 
Preparation of the manuscript in a form suitable for publication from the original 
text completed in 1956 has been attended by delays causing a lapse of 6 years from 
completion of the manuscript to its publication. For this reason references to 
pertinent literature omit consideration of a number of important papers since 1955. 
However, in view of the fact that the main intent of this report is simply to present 
the results of the study, it has been considered advisable to present this report in 
its present form. Evaluation of this study, as well as later ones conducted by me at 
the National Institutes of Health, in the light of more recent studies by others has 
been included in other papers I have recently published, or which are in preparation. 
John B. Calhoun 
Sept. 72, 7 962 
IV 
