FIELD T-3 

 Columns 62, 63, and 64 



CATEGORY OF THE TEST COMPOUND'S EFFECT 

 REPRESENTING PRACTICAL USE 



Organization 



Field T-3 symbols have three units. Because IBM sorting is more direct when only numbers 

 are used as units of symbols, letters have so far not been used in Field T-3 symbols. 



The items of Field T-3 are arranged by only three categories (i. e. , symbol series 1--, 2--, 

 3--), as defined and explained in the section on Specific Directions and Explanations. 



General Use 



In Field T-3, the chemical effect coded in Fields T-l and T-2 is described in terms of one of 

 certain broad categories of effects. Examples of these are (1) curariform effect: all specific responses 

 which are likewise caused by curare, Symbol 229; (2) parasympathomimetic: all specific responses 

 which are likewise caused by stimulation of the parasympathetic nervous system, Symbol 226; (3) 

 rodenticide: death caused to any species of rodent, Symbol 115; and (4) mydriatic action: contraction 

 of the radial muscles or relaxing of circular muscles of the iris, Symbol 222. 



The Field T-3 categories of test compound effects are defined to refer to a practical use . For 

 example, the CBCC uses the terms of Field T-3 to separate, from all information on lethal effects, that 

 information relating to practical use in population control of organisms. If information is wanted on all 

 lethal effects on any group of organisms or of any group of test compounds, sorting should never be in 

 Field T-3, but only in Field T-2, whereas, if information is wanted on compounds which might be con- 

 sidered specifically as herbicides, rodenticides, bactericides, etc. , retrieval should be only by Field 

 T-3. This distinction from coding in Field T-2 is made by all terms of Field T-3. 



One difficulty in classifying chemical effects by symbols of Field T-3 is that of interpretation 

 of the test results in coding the information. For example, although the literal meanings of herbicide 

 or rodenticide may be merely the killing of plants or killing of rodents, the categories indicated by 

 Symbols 108 and 1 1 5 of Field T-3 refer to practical control of plant or rodent populations, as explained 

 above. Thus, when a test compound is administered by injection in a rodent or a plant and death 

 results, the death by injection can hardly be considered as a practical method for control of the rodent 

 or plant and Field T-3 should not be coded with Symbol 108 or 115 to suggest that the test has demon- 

 strated practicality for those purposes. Coders have always found very difficult understanding that 

 lethal effects should be coded by the terms of Field T-3 describing killing only when the method of 

 testing represents a practical control method, whereas Field T-l and T-2 should be coded with all 

 lethal effects, whether or not caused by a method that might be practical for population control. 



A major difficulty in use of Field T-3 items is that of interpreting consistently and accurately 

 all specific physiological effects (coded in Fields T-l and T-2) in terms of the general type of 

 pharmacological effect of Field T-3. In the literature, an author commonly considers it unnecessary 

 to point out to his specialized reader that a specific response is actually adrenaline- like or 

 sympathomimetic, for example. Even coders with considerable pharmacological training who, on 

 reflection, would recognize a specific effect as being adrenaline-like or sympathomimetic are apt to 

 neglect doing so; in the case of coders not familiar with all aspects of sympathomimetic action, the 

 coding problem is even more acute. 



Specific Directions and Explanations 



1. Symbols of the 1-- series; effects connected with control of populations of the test organism ; 

 death, attraction, or repulsion as an objective in control of organism populations 



Most of the symbols of the first series of Field T-3 are used to indicate that a lethal effect is 

 the effect desired and represents the use for which the compound is tested. Since this is not true of 

 all lethal effects of test compounds on the test organism, Field T-3 serves to classify death produced 



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