Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)

liiation in such cases was rendered difficult or doubtful. (Such inconclusive cases occuring in the present study were omitted.) The test was read 48 hours after the injection. Three parameters taken into account for interpretation were redness of the skin, induration and incidental complications. First, the greatest diameter of erythema, transverse to the axis of forearm, and the longitudinal diameter, i.e. parallel to the axis of forearm were measured using a transparent ruler divided into millimetres. Then the margins of the indurated skin were estimated by palpation and diameter measurements made. Of these 4 variables (transverse and longitudinal diameters of both red and indurated areas of skin) it was the transverse diameter of skin erythema that proved most suitable for evaluation of the reaction.This is in accord with experiences obtained with the tuberculin test (WHO, 1963). The transverse diameter has the advantage that its size is determined mainly by the reaction whereas the longitudinal one is largely influenced by the morphological structure as well as the actual function of forearm. The longitudinal diameter, in particular that of redness of the skin, is generally greater than the transverse one. That is why the red area of skin is oval instead of circular,the longer diameter being parallel with the axis of the forearm. This is particularly to be taken into account for interpreting inconclusive reactions. In about 2-3 # of the injections a small red spot was noticed on the skin around the needle puncture; the transverse diameter of the red spot varied between 2-5 mm,These changes were probably due to incidental infections associated with intradermal injections.The longitudinal diameter is longer also is such cases and estimation .of this parameter may cause difficulty in distinguishing true positive reactions from negative ones. Nevertheless, as the transverse diameter of skin redness does indicate the characteristics and degree of the reaction we consider that reading of the latter parameter is