Page:Proceedings of the Royal Society of London Vol 60.djvu/444

412 spheres be carefully removed, e.g., from a monkey, with avoidance of haemorrhage and of fall of body temperature, and if sufficient time be allowed to elapse for subsidence in the animal of w hat may be called immediate shock, movements can be evoked remarkably different from those I have ever seen elicitable as purely spinal or as cerebral reactions. If a finger of one of the monkey’s hands be stimulated, for instance, by dipping it into a cup of hot water, there results an extensive reflex reaction involving movement of the whole upper limb. The wrist is extended, the elbow flexed, the shoulder protracted, the upper arm being draw n forward and somewhat across the chest. The movement occurs after a variable and usually prolonged period of latent excitation. The movement, although it may be fairly rapid, strikes the observer each time as perfectly deliberate ; it is of curiously steady and “ smooth ” performance. Sometimes it is carried out quite slowly, and then, as a rule, the extent of it is less ample. The most striking feature of the reflex is, however, that when the actual movement has been accomplished the contraction of the muscles employed in it does not cease or become superseded by the action of another, but is continued assumed suggests the taking of a forward step in quadrupedal progression, and in that posture the animal will remain for a quarter of an hour at a time.

The degree of, for instance, flexion assumed in the new posture seems m uch dependent on the intensity and duration of the stimulus applied. If the degree is extreme, the attitude of the limb may not be m aintained to its full extent for the time mentioned ; thus, the olbow, at first fully flexed, will in the course of a m inute or so be found to have opened somewhat. This opening can be often seen to occur per saltum, as it were, but the steps are quite small, and recurrent at unequal intervals of between perhaps a quarter of a minute and a m inute. A fter some relaxation from the extreme phase of the posture has taken place, the less pronounced attitude, semiflexion a t the elbow, may persist w ithout alteration obvious to inspection for ten minutes or more. A part from the occasional step-like relaxations, the contraction of the muscles is so steady as to give an even line when registered by the m yograph. A renewed stim ulation of the finger excites further flexion, which is m aintained as before in the way above descxubed. The posture can be set aside w ithout difficulty by taking hold of the limb and unbending it; the resistance felt in the process of so doing is s lig h t; the posture thus broken down is not reassumed when the limb is then released.

Analogous results are obtainable on the hind limb. H ot water