Many normal-sighted persons might object to the inclusion of some of the colours on the orange card, but this card clearly shows the colours which may be taken as a match. Fine distinctions are not wanted. The series of colours I have selected and arranged so as to confuse the colour-blind and force them to be guided by their colour-perception, whilst the quantity of colour is amply sufficient for the normal-sighted to pick out the colours with the greatest ease. The cards should be arranged irregularly on a white cloth in a good light. The two most important tests colours are the Orange and Violet, Nos. I and II. The person examined should be asked to point out the shades of colour similar to No. I (Orange). A piece of paper rolled to a point should be used for this purpose. If he do this correctly, he probably possesses normal colour-perception. If, however, he match the test with reds or pinks, he is more or less colour-blind, at best belonging to the pentachromic class. If, in addition, he match the Violet test, No. II, with blue, he at least belongs to the tetrachromic class. The trichromic, in addition, may match the Blue-green test, No. III, with brown and grey. The dichromic will match the Orange test, No. I, with yellow-green and yellow-brown. Similar mistakes will be made to those described in connection with the Classification Test. The examinee should be asked to name all the colours on one of the cards. He should also be asked to point out on which of the cards the four test colours are to be found, and which contain none of the test colour. The examiner should continually change the order of the cards. Most of the varieties of the colour-blind will be readily detected in this way. The special advantages of this test are: (1) The colour-blind can be ranged definitely in their proper classes. (2) Central scotoma can be detected with its aid. (3) The series of colours are arranged so as to confuse the colour-blind, whilst the normal-sighted easily match the test colours. (4) On account of the introduction of different materials, the relative luminosity and saturation of colours does not serve as a guide to the colour-blind. (5) Portability. (6) The wools and silks are kept clean. (7) An important colour is not likely to be lost.