Practically all the chapters in this volume present. It is possible that the cerebral contain new and previously unpublished system has a neurotransmitter role, espe- research reports and reviews on the phys- cially as intracerebral angiotensin-induced iological mechanisms which induce drink- drinking seems to depend on catecholami- ing of non-nutritive fluids. Though based nergic, perhaps dopaminergic, systems. on a Symposium on Thirst we have not However, we were also reminded that called the volume by this title because there are cholinergic drinking systems in thirst as such, a subjective human sensa- the brain, at least of the rat, and that tion, is not in fact discussed in these pages. vasopressin increases the sensitivity of The main section headings in the list of drinking systems in the brain of the dog. contents give an idea of the topics dealt An 'apres Cannon' role for oropharyn- with and it is evident from these that a geal factors in the control of water intake is large number of contributions deal with becoming firmly established. There is a the possible role of the renin-angiotensin need to take water by mouth. The self-in- system in the control of water intake. One travenous injection experiments described difficulty until now in accepting the sugges- here make this very clear.