FIELDS G-l and G-2 

 Columns 27 and 28 



subsequent to an initial exposure. The CBCC, however, codes the description of the initial 

 exposure that produced the resistance or sensitivity. Therefore, when coding these actions 

 (Field T-2, symbol series 51-- and Symbol 58), Field G is never coded with Symbols 6 or J, 

 since at the time of that initial exposure (when the resistance or sensitivity was produced), 

 the state of resistance or sensitivity did not exist. 



12. Symbols F, G, H, and I represent characteristics intrinsic to the test organism and do not 

 represent responses to the test compound 



Symbol G is not used when coding the production of cross tolerance by a test compound. Symbols 

 F, G, H, and I are used only for strains that have naturally the attributes indicated or that have ac- 

 quired the attributes prior to the experiment with the test compound, not for individuals made resistant, 

 sensitive, dependent, etc. , during the course of the treatment being coded. 



As indicated in the definition for Symbol G, the four symbols, F, G, H, and I, are for distin- 

 guishing physiological strains only (such as "resistant strain", "sensitive strain", etc. ). They are 

 never used to distinguish a taxonomic strain (a breed of dogs or cows, a strain of bacteria, etc. ). 

 The CBCC Code does not distinguish taxonomic strains of test organisms and when a strain _is given a 

 special symbol in the Taxonomy Code, it represents an exception for which there has seemed adequate 

 justification. The special use of Symbol F, described in Division 9, is not an exception to never indi- 

 cating taxonomic strains by Field G, since it permits distinguishing a group of responding taxonomic 

 strains from a group of unresponding taxonomic strains and therefore is really distinguishing organisms 

 by a physiological characteristic. 



Occasionally, even a physiological strain can be given a special symbol in the Taxonomy Code 

 (e. g. , the DDT-resistant housefly). Symbols F, G, H, and I need not be used if the test organism is 

 of a physiological strain (resistant, sensitive, etc. ) which _i_s already adequately indicated by a special 

 distinguishing symbol in Field E. 



13. Test organisms, organs, or tissues WITH INCIDENTAL IMPLANTS 



Symbol S is used to indicate that the organism, organ, or tissue responding to the test compound 

 has incidentally a structure implanted in it, regardless of whether the implanted structure is normal, a 

 tumor, or a pathological structure, or causes a pathology, as long as the response of that implant to the 

 test compound is not being coded. For example: There are reported observations on a compound's 

 toxicity to mice with tumor implants (the tumors having been treated with the compound as a candidate 

 carcinostat). In coding the toxicity, the mouse is coded in Field E, the toxicity response in Fields T, 

 X, and Y, and Field G is coded with Symbol S. 



14. Test organs or tissues Incidentally IMPLANTED into organisms, organs, or tissues 



Symbol T is used to code the implantation of a normal organ, tissue, or cell into another 

 organism, organ, or tissue, when the response of the implanted organ, tissue, or cell to the test 

 compound is being coded and when Field J is not coded because the implant and the organism receiving 

 it may be considered as a normal biological unit rather than as a host-parasite or host-pathology 

 relationship. Since these implanted structures are the responding structures (and their implantation 

 is their experimental state), they will be coded in Fields H-l or I. This situation is given definition 

 here and assigned Symbol T for sake of completeness, though it is improbable that frequent occasions 

 will arise to use it. Symbol T might be used if chemicals are tested as means of making an implant 

 successful; tissue grafts or organ implants, either embryonic or adult, might be given local chemical 

 applications which would be candidate to assist the implant in establishing. (In this example, Field 

 T would be coded to indicate prevention, by the test compound, of the atrophy or other fate the 

 untreated implant would meet; Field G would be coded with Symbol T to indicate that the organ or tissue 

 in Field H-l or I was an implant. ) 



(When the implanted structure is [1] not normal, i. e. , is [a] a tumor or [b] otherwise pathological 

 or [2] if the implant brings about a pathological condition and there is being coded the response [to the 

 test compound] of that tumor or of the pathology of the implant or of the pathology caused by the 

 implant, the tumor or pathology will be coded in Field E and Field G will not be coded with Symbol T. ) 



56 - 



