Ishihara Color Test, 38 Plate Edition, by Shinobu Ishihara, M.D., Dr. Med. Sc., Professor Emeritus of the University of Tokyo, and member of the Japan Academy. Dr. Ishihara's color perception tests are recognized internationally as a highly reliable method of determining color deficiency. The numerals which are seen on plates 1-25 are stated, and each answer should be given without more than 3 seconds delay. If the subject is unable to read, plates 26-38 are used and the winding lines between the two x's are traced with a brush. Each tracing should be completed within 10 seconds. It is not necessary in all cases to use the whole series of plates. Plates 22, 23, 24 and 25 may be omitted if the test is designed merely to separate those with defective color appreciation from those with normal color appreciation. In a large scale examination the test may be simplified to an examination of six plates only Number 1, one of Numbers: 2, 3, 4, 5, one of Numbers: 6, 7, 8, 9, one of Numbers 10, 11, 12, 13, one of Numbers: 14, 15, 16, 17, and one of Numbers 18, 19, 20, 21. It may be necessary to vary the order of the plates if it is suspected that there is a deliberate deception on the part of the subject. These hard cover books come with complete instruction booklet.