Practical electro-therapeutics and X-ray therapy - with chapters on phototherapy, X-ray in eye surgery, X-ray in dentistry, and medico-legal aspect of the X-ray (1912) (14570435258)

Identifier: practicalelectro00mart (find matches)

Title: Practical electro-therapeutics and X-ray therapy : with chapters on phototherapy, X-ray in eye surgery, X-ray in dentistry, and medico-legal aspect of the X-ray

Year: 1912 (1910s)

Authors: Martin, James Madison, 1866-1947

Subjects: Electrotherapeutics X-rays Diagnosis, Radioscopic Eye Electric Stimulation Therapy X-Ray Therapy Ophthalmologic Surgical Procedures

Publisher: St. Louis : C.V. Mosby

Contributing Library: Francis A. Countway Library of Medicine

Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

Text Appearing Before Image:

he charges are prevented fromuniting by means of the waxed paper. When the condenser isused, the current is offered a path of much less resistance, and, in-stead of jumping across the air gap at the contact between thescrew and spring 3, it goes into the condenser. The condenser notonly provides an open path for the extra current, but furnishes areverse current that effectively demagnetizes the coil core. Allfaradic coils intended for physicians use should be provided with 42 PRACTICAL ELECTRO-THERAPEUTICS AND X-RAY THERAPY well-built condensers. One or more secondary coils may be oper-ated from around a primary. The faradic coil usually found in the physicians office consistsof a primary winding of about 250 feet of No. 20 copper wire,which is covered by a secondary of about 4,500 feet of No. 36 cop-per wire, the latter being tapped at 1,500 and 3,000 feet. Thesedifferent lengths are connected with a selective switch in such amanner that they may be used separately and independently.

Text Appearing After Image:

Fig. 14.—Simple faradic coil, with the addition of a secondary coil. Fig. 14 is a reproduction of the coil in Fig. 12, with the additionof two secondary coils F and H. The various lengths of this coilare controlled by the selective switch G. The necessity for thedifferent lengths of the secondary becomes obvious when it is un-derstood that in the action of the coil each additional coil of wireincreases the voltage of the secondary current. By constructinga secondary, so that several different lengths of wire may be used,the particular tension necessary in a given case may be selected atwill. The physiological effects of these coils differ widely. The MAGNETISM AND ELECTROMAGNETISM 43 longer the wire, the higher the tension and the more marked thesedative effect, while the current from the short thick wire of theprimary coil is stimulating and nutritional. This subject will bediscussed at length under therapeutics of the faradic coil. CHAPTER IV. ELECTROSTATICS. Thus far electricity

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1912

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