_Concussion_.--Temporary loss of function was often observed in the limbs, corresponding to the distribution of one or more nerve trunks when wound tracks had passed in their vicinity. Interference with function sometimes amounted to loss of sensation alone: in others to loss of both sensation and motor power. Such symptoms were of a transitory character, lasting for a few days or a week; if both sensation and motion were impaired, sensation was usually the first to be regained. In these cases secondary trouble was not uncommon, since the near proximity of the track to the originally affected nerve offered every chance for implication of the latter in the resulting cicatrix. This sequence was often observed, and its symptoms are described under the heading of secondary implication below. Equally striking were the instances of concussion in the case of the nerves of special sense and their end organs, temporary loss of smell, vision, or hearing being not uncommon, often passing off in the course of a few days with no apparent ulterior ill-effect. One of the most interesting illustrations of the occurrence of concussion was furnished by cases in which complete paralysis of a limb rapidly cleared up with the exception of that corresponding to a single individual nerve of the complex apparently originally implicated. Instances of severe contusion or division of one nerve of the arm, for instance, accompanied by transient signs of concussion of varying degrees of severity in all the others, were by no means uncommon. _Contusion_.--The symptoms of contusion were somewhat less simple, since, in addition to lowering or loss of function, signs of irritation were often observed. In the slighter cases irritation was often a marked feature, as was evidenced by hyperaesthesia and pain combined with loss of power. In cases in which pain and hyperaesthesia were primary symptoms, these were often transitory. I will quote an illustrative case which, though affecting the nerve roots, is characteristic of the effects of slight contusion in the case of the nerve trunks in any part of their course:--