FIELDS M and N 

 Columns 45 and 46; 

 47 and 48 



General Use 



Field M is used in cases when the test compound is applied in a diluent or carrier so that the 

 quantity must be expressed in terms of a concentration of the test compound in the preparation admin- 

 istered. In case a compound is administered at 100% concentration (i. e. , lacking any diluent) and 

 the quantity is unknown so that it can not be expressed in Field N, Field M may be coded with Scale 4, 

 Symbol 9. 



Field N expresses the amount of pure compound administered to the biological component of the 

 test within a given unit of time expressed in Fields O and P. This field is used, therefore, when the 

 test compound is applied in a pure and undiluted form - -so that the concentration is always 100% -- and 

 when the quantity of this is known. However, Field N is also used to express the amount of pure 

 compound represented by the total dose when administered at a given concentration less than 100% 

 (the concentration being always expressed in Field M). The quantity in any case is always expressed 

 in Field N in terms of amounts of the pure compound, such as pounds, grams, milligrams, etc. 



Specific Directions and Explanations 



1. Both concentration and quantity coded when possible 



An author will seldom record both the concentration of the test compound preparation employed 

 and the quantity of the test compound applied per organism, but he will often give information on the 

 concentration in such a way that the quantity applied per organism can be calculated or will give 

 quantity- dosage information from which concentration- dosage information can be calculated. When 

 both concentration-dosage and quantity-dosage information are available or can be calculated, both 

 should be recorded and coded. 



2. S election of the scale (i. e. , the unit of measure) when the author's unit of measure can be 

 converted; Field M Scales 1, 4, B, and 5 



In Field M, some concentrations can be expressed, though not equally well in all cases, with 

 any one of several scales by mathematically converting the dosage values. These are Scales 1, 4, 

 and B. (Scale 5 represents a unit of measure, pounds/100 gallons, which can be converted to the units 

 of measure of Scales 1, 4, and B, but the probabilities of frequency of such conversion is very remote. ) 

 In Field N, none of the scales represent units of measure that can be converted to the unit of measure 

 of another scale, except that when a dose of more than 81 micrograms (= 0. 081 milligrams) is admin- 

 istered, for example, Scale 2 (the milligram scale) or Scale 4 (the gram scale) is used, since the 

 microgram scale range is limited to a maximum of 81 micrograms and the milligram scale begins with 

 0. 081 milligrams (= 81 micrograms). Therefore, a dose of 200 micrograms, for example, would be 

 "converted" to 0. 2 milligrams and coded by Scale 2. In the case of Field M, when an author expresses 

 dosage in units other than those represented by Scales 1, 4, 5, and B, there is no choice but to use 

 the scale for the unit of measure used by the author. 



In regard to making a choice of one of the Scales, 1, 4, B, and 5, of Field M, there should be 

 considered whether greater accuracy of expression can be made with one of the scales. As an illus- 

 tration, 4000 ppm (Scale 1 of Field M) would seldom be coded by use of Scale 1, since it could only be 

 interpreted as > 2525 and it might therefore represent any concentration from 2526 to 1, 000, 000 ppm. 

 By converting it to 0. 4%, it can be coded so that its interpretation is at least limited to between 0. 1% 

 and 1. 0% (Scale 4). Within the overlapping parts of the total ranges of Scales 1, 4, and B, it is 

 probably not too important as to which scale is used. For example, 100 ppm might be converted to 

 0. 01% or to 0. 1 mg/ml and, in code, this would be Symbols 16, 4_5, or B5, respectively. Thus, the 

 code symbol for the quantity unit (underlined in the symbols) varies only by one digit (or at most two, 

 with other dosage values) and this difference is not actually significant to evaluation when it is based 

 on dosage (Field Y), since such evaluation accuracy is not pretended by this Code. 



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