Aubrey Lewis's report on his visits to psychiatric centres in Europe in 1937.

I visited Van der Horst's clinic. He struck me as much more alert than Bouman, and is, I gather, more popular with the students. The researches of which he told me were concerned with electrical reactions in cats that were being treated with insulin, and the neurological findings in their hypothalamus; also the effect on neurotics of air of different ionic concentration, humidity etc. I gathered that in both of these researches the work had not yet really begun. I think he is also proposing to observe the electroencephalogram in monkeys poisoned with mescaline. I got the impression in many places that a great deal of research is arrived at by the process of saying to oneself, "A investigates B or uses method B; X investigates Y or uses method Y: I will investigate B and Y together or use B and Y." His chief psychologist, Van Essen, who succeeded Grunbaum, is an enthusiastic young man, whose training had been at first in comparative psychology under Van Boutdendyck [sic] and thereafter in Vienna under Karl Buhler for 3 years, where he wrote his thesis on 'The psychology of decerebrate birds." He seems to have a free hand in his psychological researches on time relations of motor performance, and is to assist Van der Horst in proposed investigations of the Berger Rhythm2 and in other electro-physiological work, though he seemed to me to have little intimate knowledge of the technique and principles. Van Essen though without medical training also runs a pedagogic child guidance practice, to which children are referred by doctors. He is also working on reaction time in three tempos, following on some of Van der Horst's earlier studies on cyclothymia and schizophrenia and American tapping tests. He and Van Hasselt in the histological department are, as far as I could gather, the only two assistants who have remained