512 APPENDIX 



source of supply of inbred mice, tumors, and mice with mutant genes to investigators 

 throughout the United States and abroad. Therefore, it is a natural target for queries 

 concerning the nature and uses of this material. Gradually it became apparent that 

 these queries should be channeled through the library and answered by means of the 

 subject-strain bibliography. In addition to answering specific questions by mail, the 

 librarian supplies a bibliographic supplement to Mouse News Letter every six months, 

 listing selected accessions during the previous six months. 



To facilitate searching the literature, more than 3,000 references were analyzed 

 in detail to determine the fields of knowledge to which investigations using mice have 

 contributed and the types of mice and tumors used in such work. A classification 

 system was devised including all of the fields and types recognized in this analysis, and 

 allowing for reasonable expansion. The key for this system lists in addition to all of the 

 inbred strains (8 major headings, 25 minor, and other), 85 subject headings, ranging 

 from aging and antibiotics through maternal influence and metabolism to tumor 

 incidence and viral studies. There are 31 major subject headings and 17 indirect- 

 sorted fields for subdivisions of fields of interest, such as 9 types of carcinogens, 27 murine 

 diseases and human diseases studied in mice, 7 subdivisions of endocrinology, 1 1 types 

 of life-history effects, 12 subdivisions of nutrition, 19 organs and systems, and 6 divisions 

 of uses and effects of radiation. Pertinent references on all of these subjects or inter- 

 actions between them can be sorted out rapidly by a small number of insertions of the 

 stylus into the 5 by 8 inch specially printed Keysort cards on which the bibliography 

 is classified (figure 70). 



References are added to the bibliography as they appear in the literature. The 

 Laboratory receives about 180 periodicals in the fields of biology, cancer, medicine, 

 and psychology. These include 12 translated Russian periodicals and 14 abstract 

 and reference tools, such as Biological Abstracts, Nuclear Science Abstracts, Index Medicus, 

 and Zoological Record — Mammalia. In addition to these, an active reprint collection now 

 containing over 30,000 items is maintained. The librarian scans these journals as they 

 are received, writing a card for each pertinent reference and classifying the paper. 

 The information on these cards is eventually transferred to the Keysort cards, which are 

 punched according to the classification noted. A skillful operator can type 50 such 

 cards per hour and punch 100 per hour. It is believed that through close scrutiny of 

 the reference periodicals, scanning 166 other journals, maintaining an aggressive 

 reprint accession policy, and utilizing bibliographies in published papers, few pertinent 

 papers will be missed. The bibliography now contains about 16,500 references. A 

 modification of this system is easily adapted for personal or departmental needs or other 

 methods of sorting. 



It is expedient to separate the cards according to periods of time: prior to 1930 

 (the earliest reference is dated 1906), 1930-1934, 1935-1939, 1940-1944, 1945-1949, 

 and yearly thereafter. This device often helps the searcher considerably by eliminat- 

 ing periods of no interest. The original hand-written cards are maintained as a separate 

 author file. The latter is indispensable for such queries as "I know John Q. Smith 



