The study of biogenic amines, which from the beginning of modern pharma- cology has always attracted the enthusiastic attention of research workers and has led to some of the most brilliant and illuminating experimental results in biology, has been unexpectedly extended in the last fifteen years. 'With the discovery of 5. hydroxytryptamine (enteramine, serotonin), in fact, the vast field of indole- alkylamines has been opened up for research. In a decade of intensive and dedicated work, an immense amount of experi- mental data has been collected, the significance of which, having rapidly...