But in the casualty clearing stations one sees three conditions in particular which are rarely or never seen at base far back. They are abdominal wounds, the early and severe effects of "gassing," and finally shock;' and shock is seen to an extent unparalleled in the experience of any surgeon at home. The very frequency of it, and the terrible nature of it, were impressive, and, not less so, our inability to rescue such patients when the degree of shock was really serious.In what is here said to-day we do not pretend to bring forward anything particularly new, -but we -have thought that a general review of these cases of shock from the clinical side, with notes upon such methods of treatment as we are able to carry out, might be, particularly at this time, of interest to the members of the Association. In addition, we would like to resume, briefly, the prevailing theories concerning shock, and to offer in the light of our clinical experience a few suggestions concerning these theories.In order to get a better comprehension of the conditions under which we did our work, let us relate, very shortly, the manner of evacuation of the wounded from the trenches to our casualty clearing station, situated some six to eight miles behind the front-line trenches. The wounded soldier is usually carried without delay by the battalion stretcher bearers down a communicating trench to the dug-out of the battalion medical officer situated 400 or 500 yards back. Here first aid is given, and then, if possible, the man is carried, still by stretcher bearers, for another 40o or 500 yards back to a point where a horse ambulance is waiting. This can, of course, usually be done only at night, and there is sometimes a long delay while waiting for darkness. The horse ambulance works back another mile or so to a point where it is safe for motor ambulances to wait. Here another transfer takes place. The motor ambulance then brings its load to field ambulance headquarters, or, if the wounds are serious, straight