There is no discussion in Stevens' (16) or Osgood's (14) textbooks of experimental psychology of the contribution of cortical functions to the production of visual after-images. Woodworth (19) presents a theory of after-images involving the cortex in the first edition of his book. It is not repeated in the second edition. There is, however, a large number of reported studies indicating the importance of cortical functions in the production of after-images (e.g. 1, 3, 6, 9, 11, 12, 13, 15, 17). In view of these studies it was decided to use the afterimage in a further attempt to verify or disprove the drug action hypothesis advanced by Eysenck in a previous paper (2). This hypothesis stated that stimulant drugs increased excitatory potential and decreased inhibitory potential, while depressant drugs decreased excitatory potential and increased inhibitory potential.

Earlier work from this laboratory showed that rheomelanins (blood soluble melanins) form in normal and schizophrenic blood incubated with the catecholamines, with l-dopa, with adrenochrome and with adrenolutin-monohydrate (Hegedus and Altschule (1–4)). This work also showed that the erythrocytes of many patients with a diagnosis of chronic schizophrenia are abnormally susceptible to the haemolytic effects of the rheomelanins or their precursors, formed in their bloods during incubation with most of these chemicals (Hegedus and Altschule (2, 4)). Erythrocytes of the chronic patients showed especially marked haemolysis during incubation of their oxalated blood with adrenochrome, with adrenolutin-monohydrate and with dopamine. A test for routine use was developed on the basis of this phenomenon, and is reported in this paper. The conditions of this routine test were determined as regards quantity of chemicals, time and temperature of incubation, and rate of shaking during incubation so as to give maximum differences between normal and schizophrenic bloods.

Most clinical psychiatrists would agree that many but not all schizophrenic subjects show abnormalities in the field of language. Many use neologisms, i.e. new words for old referents, and some chronic patients talk in a more or less private language which at times degenerates into a word salad. The following features have been noted in the schizophrenic's verbal productions—alliteration, condensation, over-inclusiveness and the personal distortion of the symbol-referent tie. Stuart Chase said: “The point of every discussion is to find the referent. When it is found emotional factors dissolve in mutual understanding.” Psychiatrists often assume that they have identified the referent which ties in with the symbol the patient is using, but sometimes the patient uses new symbols, as “Bill” did the other week when he astonished the other group members by announcing that he was “troubled by warpations and distressed by ignorances”.