FIELDS W, X, and Y 



Columns 68; 69 and 



70; and 71 



cent increase over a normal condition, since these are abnormal conditions induced by the 

 compound; neither can the intensity be expressed as a per cent of a maximum (100%) edema, 

 pain, hyperpnea, etc. , because fixing a maximum for such responses is in most cases 

 impossible. Therefore, for such responses as death, edema, thrombosis, etc. , induced by 

 the test compound, about the only practical way of making a comparative evaluation of test 

 compounds' potencies is by comparing threshold doses of the compounds (i. e. , ignoring 

 the intensities of edema, hyperpnea, etc. ), using Criterion 20. (If intensity of such a 

 response is to be coded, it can only be by terms such as "mild", "fair", "severe", etc. , 

 Criterion 01. ) 



However, if the action of the test compound causes an increase or decrease of a normal 

 physiological function or an increase or decrease of normal size, weight, or growth of the 

 organism or anatomical structure, the intensity of response can be measured and expressed 

 as the per cent increase (0% through, or greater than, 100%) or per cent decrease (0% 

 through 100%). Likewise, if the response has a known terminal point (such as the chemical 

 alterations indicated by the FE-- symbol series of Field T-2, or tumor regression, or tissue 

 regeneration and wound healing, relief from a pathology, degenerations, inhibition of 

 specific actions of secondary compound, etc. ), the intensity of response to the test 

 compound can be measured and expressed as the per cent of that terminal intensity (0% 

 through 100%). 



Thus, in an individual organism, the intensity of response can frequently be expressed 

 in definite terms of percentage of response possible or percentage of increase or decrease 

 and this might be correlated with the minimum quantity of test compound producing that 

 given intensity of response. If doses of increasing size were given to the organism in a 

 series of tests and the response in each succeeding test was shown to increase in intensity 

 corresponding to the increase in dose size, plotting the doses against the corresponding 

 response intensities would result in a characteristic curve which theoretically could be 

 compared to similar curves plotted for other test compounds and to which could be assigned 

 a code evaluation. Note that the CBCC has devised no special mechanism (i. e. , a standard 

 graph or grid) for making this evaluation by comparing these dosage-response intensity curves 

 and therefore no criterion in Field X derives an evaluation thereby. However, evaluations are 

 derived by comparing test compounds by one end of this dose-response intensity curve (the 

 threshold end), in using Criterion 20 with "death" or other all-or-none response. In this case, 

 the degree of response intensity can be ignored so that plotting of the threshold dose-response 

 could be conceived as restricted to the abscissa (the dosage scale); thus, CBCC evaluation of 

 the potency of compounds according to the threshold of response is adequate by using only the 

 dosage scale. Evaluations could be derived (though the CBCC has established no criterion 

 for doing so) by comparing all compounds by the other end of the dosage-response intensity 

 curve. This latter could conceivably be done by establishing a special graph on which the 

 ordinate would be an arithmetic scale of 0-100% response intensity, divided into areas 

 representing code evaluations (as in the case of the Log-Probit Grid, described in Division 

 24, whose ordinate is a scale of 0-100% of organisms responding). On this special 

 standard reference graph could be plotted the point of maximum intensity of response of 

 which the test compound is capable (at any dose) vs. the minimum dose causing that 

 response. 



Actually, by present CBCC procedures, potency of a compound for a given biological 

 action is a quality that the interpreter of the code line can judge only by consulting both 

 the dosage fields (M, N, O, and P) and the fields recording response intensity (U, X, and Y); 

 the two factors are never correlated to derive a Field Y evaluation coordinate, in the case 

 of a response of the individual. 



184 



