FIELD T-2 

 Columns 58, 59, 60, and 61 



been cured or restrained and the effect is coded with Symbols 1711, 172, or 1752 in Field T-2. The 

 definition of Symbol 1754 approaches the expression "prevention of death", since it is concerned with 

 a decrease in incidence of death; as the Code indicates, however, Symbol 1754 should never be used 

 unless for some reason it seems inadvisable to interpret the increase of survivors as being cases of 

 curative or restraining action of the test compound. The CBCC never codes prevention of death by 

 using Symbol 11, 111, or 112 combined with Field T- 1 Symbol 3; Division 5 explains that Symbols 11, 

 111, and 112 have always been restricted for coding death caused by the test compound. 



Although the CBCC has not made exception to the rule that Symbols of the 16-- and 17-- series 

 should not be used when tumors are coded in Field E, it is recommended that consideration be given, 

 for future use, to permitting Symbols 162, 1621, 1631, 1751, 1753, and 1754 to code effects on accel- 

 eration and retardation of the tumor (as contrasted to effects on increase and decrease in ultimate size 

 of the tumor), and on death due to the tumor coded in Field E. 



14. Symbols of the 18-- series; coding of effects of the test compound on the population of 

 microorganisms on a non-living host 



Symbols 11, 111, 112, and 113 through 117 in general describe toxic effects, including 

 death, as they are produced in individuals . The symbols are never used to code death or toxic effects 

 on a microorganism; in the case of tests on microorganisms, most determinations of toxic effects are 

 expressed in terms of the effect on a mass population of the organism and these test results most 

 frequently are in terms of effects on the normal growth of that mass. 



Toxic effects on microorganisms are coded by symbols of the 17-- series, in the sense that, 

 when the pathology treated by the test compound is an infectious disease, a cure (or reduction of num- 

 ber of individuals of the pathogen) represents a selective lethal effect on the pathogenic microorganism. 

 However, since symbols of the 17-- series are restricted to coding effects on pathologies, the symbols 

 are restricted to coding toxic effects of the test compound on pathogenic microorganisms in living hosts . 

 This leaves need for a provision to code toxic effects of the test compound on non-pathogenic micro- 

 organisms and toxic effects of the test compound on microorganisms (pathogenic or non- pathogenic) on 

 non-living hosts . 



For this purpose, symbols of the 18-- series have been provided. The definitions of the symbols 

 represent the microorganism's normal growth on any non-living "host". 



Only three symbols are included in the list for coding effects on microorganisms on non-living 

 hosts, 181 for general gross effects on the colony (i.e. , any inhibition or facilitation of the colony's 

 growth), 1812 for demonstrated lethal action, and 18 as an introductory symbol for the series which 

 can be used if it is not known whether an inhibitory effect is a lethal effect or merely a repressive 

 effect. (In inhibiting microorganisms, the action may be merely a repressing action [frequently des- 

 cribed as a static action or stasis, e.g. , "bacteriostatic"] or it may be a lethal action [a " 'cidal 

 action", e. g. "bactericidal"]. ) 



As in the case of Symbols 1 1, 111, and 112, only Symbol 7 is used in Field T- 1 with death of 

 microorganisms (Symbol 1812) in Field T-2; Symbol 1, 2, or 3 is used in Field T-l with Symbol 181 of 

 Field T-2, according to whether development is accelerated or caused to increase beyond normal 

 limits (Symbol 1), retarded in rate or decreased to a smaller ultimate size (Symbol 2), or made static 

 ("stasis"), i. e. , restrained at the stage of development in which the colony was at the time of appli- 

 cation of the test compound (Symbol 3). 



1 5. Symbols for series 28-- and 2A--; formation and size change in organs and in the entire 

 organism 



The items of Field T-2 referring to development and ultimate character of organs (series 28--) 

 and the organism (2A--) are most frequently used in cases of effects of test compounds on young, 

 developing organs and organisms. However, the symbols are not excluded for use for mature organs 

 and organisms, if the test compound has been administered to a mature organ or to the mature organism 

 and change occurs which alters the weight or volume; in particular, Symbols 281, 2811, 2A1, and 2A1 1 

 might be used to code size or weight of the mature organ (281 and 2811) and organism (2A1 and 2A11). 



143 - 



