On the Physiology of the Salivary Secretion

AN interesting paper on the antagonistic actions of atropin and pilocarpin on the sweat-glands of the foot of the cat was published by Luchsingert towards the end of last year. He showed that when the secretion induced by a sub-cutaneous injection of pilocarpin had been stopped by a subsequent sub-cutaneous injection of atropin, and the secretory nerves of the sweat-glands paralysed, the secretion could be started afresh and the secretory nerves once more made irritable by a fresh dose of pilocarpin injected locally under the skin of the foot. Hence he says (p. 488): "A definite quantity of atropin can then undoubtedly annul the stimulating action of a definite quantity of pilocarpin, but on the other hand, this so-called paralysing action of atropin is in its turn overcome by still larger quantities of the stimulating agent +." And thence the deduction that " there exists between pilocarpin and atropin a true mutual antagonism, their actions summing themselves algebraically like wave crests and hollows, like plus and minus. The final result depends simply and solely upon the relative number of the molecules of the poisons present 11"