It must be borne in mind that the symptoms as about to be detailed are successive only to some extent in the order presented. They commence generally at the lower part of the spinal cord, but immediately afterwards, if not simultaneously, are ushered in with great rapidity from other centres, masking each other and rendering it extremely difficult to observe and analyse them separately. They are also very variable through the poison concentrating its action on special centres, leaving others comparatively intact, and this not only when from different varieties of snakes, but also from snakes of the same variety. Another element increasing the difficulties of correct analysis are the depressing effects of fear, inseparable in all but the strongest minds from the consciousness of having been bitten, and so similar in appearance to those of snake-poison, that sometimes it is by no means easy to decide which of the two is in operation, and that only those cases are of real value to the observer from which this element of fear is completely excluded. A.--Action on the Anterior Cornua of the Spinal Cord. The anterior cornua are almost invariably the first of the motor-centres attacked by the snake-poison, the affection (commencing with paresis and in serious cases generally culminating in paralysis) beginning in the lumbar ganglia and taking an upward course. The lower extremities feel unnaturally heavy and a paretic condition of the muscles supervenes _simultaneously on both sides_. The walk becomes unsteady and staggering, very similar to that of persons under the influence of large doses of alcohol. By a powerful effort of the will, however, persons in this condition are often able to walk and even run for some distance, especially if by prompt ligature the absorption of the poison has been checked. As the affection proceeds, though still able to move the legs in a sitting posture, they are unable to rise again. Ere long even sitting up becomes impossible and they collapse helplessly. At this stage sensation is still intact, and reflex action, by pricking the skin, &c., still takes place. The upper extremities generally retain the power of voluntary motion, even after the muscles of the neck have become paretic and the head is held up with difficulty or sinks to one side. With birds, according to Feoktistow, the reverse is the case. The wings are usually first attacked, or paresis comes on in wings and legs at the same time. B.--Action on the Medulla Oblongata. a.--The Vaso-Motor Centre.