If earth or street dirt has entered the wound, the surface may with advantage be painted over with pure carbolic acid, as virulent organisms, such as those of tetanus or spreading gangrene, are liable to be present. Prophylactic injection of tetanus antitoxin may be indicated. CHAPTER XIII CONSTITUTIONAL EFFECTS OF INJURIES SYNCOPE--SHOCK--COLLAPSE--FAT EMBOLISM--TRAUMATIC ASPHYXIA--DELIRIUM IN SURGICAL PATIENTS: _Delirium in general_; _Delirium tremens_; _Traumatic delirium_. SYNCOPE, SHOCK, AND COLLAPSE Syncope, shock, and collapse are clinical conditions which, although depending on different causes, bear a superficial resemblance to one another. #Syncope or Fainting.#--Syncope is the result of a suddenly produced anæmia of the brain from temporary weakening or arrest of the heart's action. In surgical practice, this condition is usually observed in nervous persons who have been subjected to pain, as in the reduction of a dislocation or the incision of a whitlow; or in those who have rapidly lost a considerable quantity of blood. It may also follow the sudden withdrawal of fluid from a large cavity, as in tapping an abdomen for ascites, or withdrawing fluid from the pleural cavity. Syncope sometimes occurs also during the administration of a general anæsthetic, especially if there is a tendency to sickness and the patient is not completely under. During an operation the onset of syncope is often recognised by the cessation of oozing from the divided vessels before the general symptoms become manifest. _Clinical Features._--When a person is about to faint he feels giddy, has surging sounds in his ears, and haziness of vision; he yawns, becomes pale and sick, and a free flow of saliva takes place into the mouth. The pupils dilate; the pulse becomes small and almost imperceptible; the respirations shallow and hurried; consciousness gradually fades away, and he falls in a heap on the floor. Sometimes vomiting ensues before the patient completely loses consciousness, and the muscular exertion entailed may ward off the actual faint. This is frequently seen in threatened syncopal attacks during chloroform administration. Recovery begins in a few seconds, the patient sighing or gasping, or, it may be, vomiting; the strength of the pulse gradually increases, and consciousness slowly returns. In some cases, however, syncope is fatal.