'Adherents of cellularly-distinct conceptions of neuronal connection portrayed them as confirming associationist contentions regarding the nature of psychology. For example, US physician Francis Xavier Dercum argued that the 'amoeboid' expansion and retraction of individual cells underlay variously: hysteria; hypnotic and dream states; sleep; and trains of thought themselves. These latter, Dercum contended, appeared 'to follow purely mechanical lines' of association and disassociation between the sense impressions that they carried.'