ERHAPS the most intriguing and rewarding application of skillfully P administered and interpreted diagnostic psychological tests is in the area of aiding in the diagnosis of so-called ambulatory schizophrenia. In his pioneering book, Psychodiagnostics, Dr. Hermann Rorschach, who died in 1922, described the first case of latent schizophrenia which was identified with the aid of his famous ink-blot test. In his own words:The findings in this patient were quite surprising. She held a responsible position for many years and finally saw a physician because she had begun to suffer from "nervous complaints." The experience type is that of an egocentric extratensive individual. The type of answers given, the numerous responses involving self-reference, the repeated indication of belief in the reality of the pictures interpreted, and the emotional coloring in the answers, all these findings indicate a more introversive type. Such relationships are found in epilepsy and in schizophrenia. Epileptics confabulate and perseverate more than is the case here, however, and also have more kinesthetic answers. We can, therefore, be dealing only with a schizophrenic illness. The number of Dd, the fixation on sexual matters, the scattered sequence, the wide variability (in quality) of responses, and the tendency toward absurd and abstract replies, all these speak for such a diagnosis. From the results noted above, one would have to say that the case is one where there is marked scattering, and that the case is of many years duration so that there is now a definite schizophrenic deterioration. But this is not actually the case. All one can say is that the patient avoids correct rapport with her surroundings and goes her own way entirely and that she falls into hypochondriacal and anxious states and querulous periods. . . . This case is one in which the test is liable to confuse a latent psychosis with a manifest one. A comparison of this protocol with the examples of schizophrenic records given below will show that the results in many cases of manifest schizophrenia approach the normal result more closely than is the case in latent schizophrenia (9, p. 157).Rorschach was, of course, familiar with the contributions of E. Bleuler(2), who described the essential features of schizophrenia in terms of a primary thinking disorder and secondary symptoms, such as delusions, hallucinations, and other more florid aspects. But, primarily and basically, schizophrenia is a thought disturbance and this thought disorder, of which loosening of associations is the most prominent feature, precedes the development of the more clinically obvious secondary symptoms, the marked regression and deterioration. Robert Knight ( 5 ) has stated about the schizophrenic process that "in the early stages of such a process clinical observation may not be sufficient to detect the presence of the thought disorder, and reliance must be placed on competent diagnostic psychological testing and interpreta-