Most important action is on the blood, producing an antiplastic effect, rendering it more fluid and darker ; the red corpuscles lose their coloring matter ; the blood stagnates in the vessels and nutrition is interfered with. As a result of this deficient nutrition, the bones and periosteum become affected, the mucus membranes become involved in a catarrhal inflammation, and finally degeneration of these and of the muscles takes place. The nerve centers are also involved, giving rise to various symptoms of cerebral and spinal derangement. Characteristic symptoms.