FIELD L 

 Column 44 



demonstrates a given therapeutic action which diminishes after the initial therapy, 

 this should not be described as a refractoriness of the host, but a refractoriness of 

 the pathogen, non- infectious pathology, or tumor in Field E. The state of the pathology's 

 having been made refractory to the test compound, when recording the test compound's 

 action subsequent to the production of refractoriness, should be coded in Field G with 

 Symbol J rather than in Field L. Any production of such refractoriness to the test 

 compound should be recorded by a code line in which refractoriness production is coded 

 in Field T-2, as described in the next paragraph. 



B. Production of states of resistance and sensitivity of the host 



Any actual production of resistant or sensitive states of a host organism would never be 

 coded in a line in which that organism was coded as a host, but only by a code line in 

 which the organism is coded in Field E as a test organism in which there was induced an 

 increase in resistance or sensitivity to the test compound or a secondary compound (Field 

 T-2 symbol, symbol series 51 or 58). The coding of increase of resistance and increase of 

 sensitivity is described in Fields M and N, Division 11, in Fields W, X, and Y, Division 13, 

 and in Field T-2, Division 20. 



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

 represent responses to the test compound . (The coder is referred to Division 12 of Specific 

 Directions and Explanations for Field G, which discussion can be applied to Symbols F, G, H, 

 and I of Field L. These symbols are never used in Field L to distinguish taxonomic strains, 

 although, in the case of Field J, there is no actual need, since Field J itself distinguishes 

 taxonomic strains. See Division 9 above, however, for the special use of Symbol F in 

 condensing data into two code lines. ) 



13. Host organisms, organs, or tissues with incidental IMPLANTS . (See Division 13 of the Specific 

 Directions and Explanations for Field G. Example: Observations are reported on a compound's 

 action on intestinal helminths in mice in which had been implanted tumors, the tumor implantation 

 having been for the purpose of separate carcinostatic tests. In coding the anthelmintic action, 

 the helminth would be coded in Field E, the mouse in Field J, the anthelmintic response and its 

 evaluation in Fields T, X, and Y, and the fact that the host has an incidental implant [the tumor] 

 is coded by Symbol S in Field L. ) 



14. Host IMPLANTED in a secondary host 



Occasionally a test method involves maintaining the host (of the test organism) in a secondary 

 host. While this is very unusual, though not impossible, in the case of whole organisms as hosts in 

 chemical therapeutic tests, it is practically invariably the case that, when the "host" of the parasite, 

 non-infectious pathology, or tumor is an excised organ or tissue of the host in Field J (indicated by 

 Symbol R in Field L), that organ or tissue is maintained by a secondary, non-living "host" (i. e. , a 

 saline bath, nutrient medium, etc. ). 



Unfortunately, a second Field J is not provided for coding such a second host of the primary host 

 organism . The few occasions when it would be needed do not justify it for the CBCC's coding. At 

 most, a provision is made to express the fact that a secondary host is involved, without identifying it: 

 Symbol T of Field L. 



Since a non-living, secondary host is assumed for excised organ or tissue hosts, coding Field L 

 with Symbol R carries that implication (expressed in the definition of Symbol R). The identity of the 

 non-living secondary host (bath, nutrient medium, perfusate, etc. ) should always be included in the 

 written abstract of Field L. 



Thus, Symbol T is available for use, however infrequent it may be, when the total host organism 

 is maintained in a special secondary host organism or non-living secondary host. It is also used when 

 this total host organism is a plant maintained fn a special and basically unnatural medium for the ex- 

 perimental period (i. e. , other than the soils in which it would be given optimum support, such as plant 

 nutrient solutions, water, agar, perlite, sand, etc. ) 



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