Medical Jurisprudence, Forensic medicine and Toxicology. Vol. 1

by R. A. Witthaus; Tracy C. Becker

When we say that these wires should be properly protected we mean that such arrangements and contrivances should be used as will prevent them while in their usual position from coming into contact with dangerous objects, particularly with other wires. This may be accomplished by guard wires or in other ways. It is plainly of great importance that this should be specially cared for, and particularly in a city where there are many overhead wires, and perhaps a considerable number of dead or non-used wires. If the electricity comes into contact with one of these no one can tell where it may be transmitted or what harm it may do.

The principles which apply to these overhead wires of course apply ceteris paribus to all other electric overhead wires, and in like manner the statements made in regard to the diffusion or spreading of currents in underground wires are applicable to all methods of transmitting electricity mechanically through the ground so far as the conditions are similar. An electric current will always follow the path of best conduction, and where several paths are opened it will follow them proportionally according to the excellence of their conduction or inversely to the amount of their electric resistance.

We shall not enter here into any questions in regard to the diffusion of electricity, its transmission through fluids, water, air or other gases, nor shall we discuss the relations of good or bad conductors to electricity except so far as this relates to certain portions of the human body. An elementary knowledge of physics and electricity must be presupposed.

We can now enter more directly upon the immediate subject of this article, that is, the effect upon the human body of severe or moderately strong currents of electricity derived from artificial sources. The accidents produced by these currents may be divided into two classes, the direct and the indirect. Under the direct we place all those conditions which are apparently produced by the action of the electricity itself, such as the general shock, the loss of consciousness, the burns, etc. On the other hand, all those accidents are to be considered indirect which are not primarily due to the action of the electric current, but are only secondary results thereof. These are largely determined by the immediate surroundings and conditions at the time. Such, for example, are the surgical injuries due to falls caused by the loss of consciousness produced by the electric shock.

Indirect Accidents.

These will be considered first, as they do not demand so detailed a description as the direct. They are traumatic in character and are the result either of loss of consciousness, momentary or lasting, or of the involuntary muscular contraction which may be occasioned by the electric shock. They are among the most frequent effects of severe electric shocks. These accidents consist in contusions, fractures, dislocations, wounds, and any other injuries which may be produced from sudden loss of consciousness while in a dangerous position. Death may readily occur either immediately or as the more or less delayed result of such injuries. If the person shocked falls into the water he may be drowned, or if into the fire he will be burnt. The varieties of such accidents dependent on the sudden loss of consciousness produced by the electricity are, of course, innumerable, and their occurrence must largely depend upon the position of the victim at the moment of the shock. We see, perhaps, most of these accidents in linemen on the tops of poles or houses or in other exposed places, but persons who receive shocks when simply standing on the ground or when sitting are not exempt from severe surgical injuries other than burns. They are often cast to the ground with great violence, and not infrequently are thrown to a distance of several feet. This is caused by the violent muscular contraction produced by the electric shock, and it may occasion, like any violent push or fall, severe injuries from contact with the various objects against which they may be forced. Although much rarer, it is also possible that the violence of these muscular contractions may be such as of themselves to cause injury, as rupture of a muscle or tendon. As practically all these indirect accidents are traumatic and surgical in character, they do not differ from other accidents similar in kind, but otherwise caused, and are to be treated on the same general principles as these.

Direct Accidents.

Quite different from the indirect are the direct accidents; those produced by the immediate (direct) action of the electricity. These are of various kinds, which we shall consider separately. They may be divided into immediate and late symptoms, and they vary much according to the severity of the shock and the constitution of the patient, and the part of the body through which the electricity passes. The character of the current which gives the shock, whether constant or interrupted, also naturally has an influence on the effect.

General Principles.—A shock may be given in three ways with an ordinary galvanic battery. If the current be sufficiently strong, a distinct shock will be produced when the circuit is closed and again when the circuit is opened, while with a current of the usual strength for medical purposes, the sensation while the current is passing through the body steadily is much less and is often limited to a sensation of burning at the seat of the electrode. A shock may also (thirdly) be produced by a reversal of the current, and the shock thus caused is stronger for the same current than that produced in either of the other ways.

The strength of these shocks is shown both by the sensation produced and by the amount of muscular contraction caused. When now a shock is caused by a continuous or constant current which starts from an ordinary dynamo or other electric generator or storer, it is practically always caused by the opening or closing of the circuit, or, what is essentially the same, the diversion of a part or the whole of the current from its proper path to and through some portion of the human body causes a shock at the time of the entrance of the body into the circuit and another at the time of its exit therefrom. Shocks from reversal of current when such current arises from a constant machine might occur, but only through some peculiar accident. Hence the shocks (distinguished from any other effects of electricity) which are received by the person coming into contact with a constant current are felt only at the moment of entering the circuit (closure) and of leaving it (opening). If a person introduces himself between the two wires of an electric circuit in which a constant current is used, in such a manner as to cause the current to pass through his body, he will feel the shock only at the moment when he touches the second wire and completes the circuit, and at the moment when he lets go one of the wires and opens the circuit (unless the current be so strong or be so placed that he can divert to himself sufficient electricity to cause a shock, or, in other words, close a secondary circuit in some other way). While the current is passing through the body, although it may burn and cause tingling and other unpleasant symptoms, there is no proper shock. In other words, an electric shock is caused only by a change in the amount of electricity passing through the body or a portion thereof.