FIELD D 

 Columns 12, 13, 14, 



15, 16 and 17 



related to the particular Field T-2 symbols, but if any of these symbols of Fields T- 1 and D are on 

 any of the cards, reference must be made to the code sheets corresponding to these cards to learn the 

 identity of the compound related to the Field T-2 symbol. ) 



The only alternatives to the procedure which involves the conflicts in Field D as described 

 would be to omit coding of all but one of the major units of information (i. e. , all but one of the four 

 uses of Field D as described in the section General Use) or to provide as many fields for secondary 

 compounds as there are uses now for Field D. Neither of these has been practical for the CBCC and 

 the present multiple use of a single field has been largely satisfactory, in spite of occasional conflicts 

 and slightly greater complexity of use. 



1 1. File of coded biology data on IBM punched cards arranged according to symbols for secondary 

 compounds 



The CBCC maintains a separate file of all coded biology data (i. e. , all IBM biology punched 

 cards) in which Field D has been coded, arranged by Field D entries. Thus, there are quickly 

 retrievable biology data for any compound, or for all compounds, which have in some way been affected 

 by test compounds or which have served as standards of comparison to the test compound. The latter 

 are easily distinguished by the IBM 12 zone punch in Column 17. Further, after removing all cards 

 with secondary compounds that are standards of comparison, the remaining cards can be sorted by 

 Symbols 8, 9, A, and C in Field T-l, distinguishing the secondary compounds whose action has been 

 affected by the test compound from those whose metabolic fate has been affected. These are simple 

 and rapid card sorts, insignificant in terms of time and effort compared to the very large sort necessary 

 to retrieve secondary compounds if a special file of biology data with Field D coding were not available. 



12. Double Coding in Field D 



Double coding is not permitted in Field D. However, Symbol # or * in Column 16 or Symbol * 

 in Column 17 may be coded, in addition to the symbol for the single secondary compound, and both are 

 punched on the same IBM card. 



17 



