THE EFFECTS OF RADIATION

acetylcholine,which is the transmitter of nerve impulses passingthrough autonomicganglia. All but one of these, mecamylamine, are quaternary ammonium derivatives similar in structure to acetylcholine. Just what are the physiological mechanismsinvolved in lowering the blood pressure is still not known, so treatment is empirical. New drugs in this group appearat frequent intervals, and thosepreviouslyavailableare largely forgotten. It is hard to see what major improvementshave been made in the newer drugs. They are more readily absorbable,and a lesser bulk is needed; but otherwise there does not seem to be much changein refractorinessor side effects. They have become more expensive. Page, from an extensive experience with mecamylamine and chlorisondamine ("Ecolid"), gives his opinion as to their value in treatment. He statesthat mecamylaminewas found effective in half of the hypertensivesgiven an averagedose of 25 milligrammes. It is more effective than other ganglionblocking agents,but the neededdose from day to day is variable. Side effects such as constipation, dryness of the mouth and jerky, choreiform movementsof the arms are seen not infrequently: these can be serious and constitute a handicapin use of the drug. Chlorisondamineis a good blocking agent with regular absorption. No complications as the result of its use have yet been seen, and patientsare relatively easy to manage. Ganglion-blocking reagentsare then useful, but fail in many cases. Their side effects are disturbing.