High Frequency Apparatus Page 114

114 HIGH FREQUENCY APPARATUS tient's home. This feature is of prime importance where X-ray diagnosis is deemed advisable and where, at the same time, there is no other reason for moving the patient to the hospital. In Fig. 1 may be seen a reproduction of a portable outfit that may justly lay claim to many unique features. This is one of the lower-priced outfits but the price cannot be taken as a criterion of its value. The outfit incorporates an exceptionally fine control device which renders it well adapted to the requirements of the general practitioner or the specialist who uses the usual high frequency modalities in his work. The range of the apparatus covers everything but the X-ray and the elimination of this feature in the design is largely responsible for the low price of the outfit. The outfit is of the transformer type and it operates only on alternating current circuits; for use with direct current, a rotary converter is necessary. The rotary costs about forty dollars and its weight detracts from the portability of the outfit. The main consideration for the prospective purchaser is, therefore, to determine whether the current supply in the places where the outfit is to be used, is alternating or direct. If the latter is found to be prevalent, a modified type of portable outfit selling at the same price would serve the purpose better. The small transformer outfit described in the preceding paragraph is designed for all classes of vacuum tube, fulguration and diathermic treatments. For fulguration the outfit is ideal as the fine control enables the operator to change from a comparatively cold spark such as is used to produce a dehydrating action, to a hot and caustic spark. The principal feature of the control is found in the use of an interchangeable pair of secondary coils on the oscillation transformer. In addition to this, the "coupling" of the primary and the secondary is variable, which introduces