Surgery of Modern Warfare II. (töredék) [antikvár]

SECTION III FROST-BITE, BURNS AND SKILN GRAFTING CHAPTER XV FROST-BITE AND TRENCH FOOT FROST-BITE WHEN the body, as a whole or in part, is exposed to cold the pathological effects which ensue are best understood if they are divided into two sections, general and local, with the recognition that general effects may follow total or partial exposure and local effects may have general ones superimposed. The maintenance of an appropriate body temperature is a prime necessity of all forms of warm-blooded hfe, and so efficient are the means adopted to this end that very prolonged exposure to severe cold is necessary before t he balance between heat production and conservation and heat loss becomes disturbed, so that the body temperature falls. General effects of exposure to cold can be subdivided into two categories : (1) those which occur when the exposure is not severe enough to lower the general temperature ; (2) those which follow when the body temperature continuously falls. In the former group are placcd some of those illnesses which occur chiefly in the winter months and which mainly affect the respiratory tract. Many of these are jirimarily infective conditions, and what part cold plays in their incidence is not sufficiently determined. In the common \rinter cold, for instance, it is possible that the inspiration of cold air renders the nasal and other respiratory mucosas less able to withstand the attack of the invading organisms or viruses ; in other examples of " winter complaints " there may be some general lowering of vitality and of resistance to infection, but undoubtedly other factors than cold, i.e., lack of sunshine and fresh air, here plaj' their part. When the exposure is so severe that it produces a heat debt and the body temperature falls, a set of much more urgent and serious symptoms arises. According to those who have had an opportunity of observing such cases, there is at the onset a loss of energy and a feeling of great fatigue ; this is often associated with a loss of the normal urge to struggle for life, so that the victim resigns himself to his fate. When the body temperature falls to about 68° F. there is an overpowering desire to sleep, and coma shortly supervenes-Those few who have survived these experiences state that the sensations are not unpleasant. Apparently life may be maintained for some time in this state, for recovery has been shown to be possible after several hours' unconsciousness. This agrees with observations on animals found " frozen " which revive when the temperature is raised. Experiments on animals subjected to severe general cold show that respiration, after an initial quickenmg, slows and finally ceases, while at a slightly later period the heart-beats (ventricular) also slow and stop. Such animals are not beyond resuscitation, even after several hours, and may be apparently unaffected by their experience. Below a certain temperature the thermal controlling i8 153