ELECTRICITY

201

1. The Nature of the Current.—Currents generated at high voltages
are dangerous to life. Alternating currents are considered more dangerous
than continuous currents, probably because they are usually generated at
high tensions; but continuous currents of high tensions are equally
dangerous under similar circumstances. Bettelli9 considers that alternating
currents of low periodicity are dangerous even at low voltages, but the
danger diminishes with the increase of frequency even when generated at
high voltages.

In addition to high voltage, long duration and close contact are the f
essential features of danger from electric currents. *

In continuous currents shock is produced at the moment of the opening
and closing of the circuit. In alternating currents it is also produced at each
reversal of the machine.

Many of the fatal accidents have occurred from currents carrying more
than 1,000 volts, but cases are recorded, where death has resulted from

currents of 200 or even lower volts. In such
cases the victims were mostly standing in
water or on damp ground^ and were thus
well " earthed ". Professor Jellinek mentions
the case of a man who was killed by a cur-
rent of 95 volts, when standing with wet
boots in a mixture of potash and sugar in a
factory at Prague. On the other hand,
recovery has occurred after the passage of a
current of 2,500 volts and even of 5,500
volts. Fitzsimons30 records the case of a
man, through whose body a current of 20,000
volts passed at a colliery. He recovered
consciousness after twenty minutes' artificial
respiration. He was none the worse after a
few days, except for a large piece of flesh
which sloughed from the sole of one of his
feet. He was standing at the time of the
shock on a dry concrete floor, but totally
unprotected as regards gloves or rubber
shoes.

The danger of a person in a bath touching
a defective electrical switch in consequence
of the water and bath furnishing a perfect
" earth " for the current is well known.

Fig. 74.—Lesion of hand from
contact with a live current of
250 volts. (From Pathological
Museum, King George Medi-
cal College.)

A girl, aged 17 years, on going to her bath took an
electrical neater with her to warm the bath-room.
After a few minutes her mother heard screams and forced the door open. She found
the girl unconscious in the bath with the heater on the top of her. She was removed
to hospital where she died. A woman, 23 years old, took a book and an electrical hair
drier to her bath-room. Her father found her with the drier in her right hand and the
book at the end of the bath. When he touched her, he got a shock himself, the handle
of the drier being saturated and the current still on,11

Judicial electrocution is the form of execution employed in the United
States of America. For this purpose the condemned criminal is seated and
strapped in a strong chair, and an alternating current of 7J amperes at a
pressure of 1,700 to 2,000 volts is, as a rule, passed three times for about
thirty seconds through the body by means of metal electrodes placed over
the head and round one leg.

9. Lewis Jones, Medical Electricity, Ed. TH, p. 315.

10. Brit Med. Jour., Nov. 15, 1924, p. 932.

11. London Correspondent, Jour. Amer. Med. Assoc., March 11, 1933, p. 752.