text and the drawing being, of course, part of the said invention: 

              Fig. 1 is a schematic section showing an apparatus for production and emission of an electromagnetic field combined according to the invention. 

              Fig. 2 is a frontal elevation of the cathode, taken from the right of Fig. 1. 

              Fig. 3 is a section through III-III in Fig. 1. 

              Fig. 4 is the overall scheme of the electric supply. 

              Fig. 5 is a view analogous to Fig. 1 showing another mode of implementation. 

              Fig. 6 is a section through VI-VI in Fig. 5. 

              Fig. 7 represents schematically an apparatus for pulsing the electric current. 

              Fig. 8 is the circuit of an amplifier permitting activation of the apparatus of Fig. 7 at the cardiac frequency. 

              Fig. 9 is the circuit of an oscillator permitting modulation of the electric current according to a wavelength between 1 m and 18 m. 

              The assemblage of Fig. 1 contains an apparatus 1 emitting electrically charged particles 2 in a cavity or passage 3, a cyclotron 4 accelerating the particles 2 and sending them into a cavity 5 forming a tube into which merges another cavity 6 acting as wave-guide for electromagnetic radiation of frequency in the centimeter range emitted by a magnetron 7.  The cavity 8 formed by the joining of tube 5 and waveguide 6 leads into a tube 9 in which the resulting radiation is accelerated and aligned.  The interior of the cavity-formed by the assemblage of elements 1, 3, 5, 6, 8 and 9 contains argon at a pressure of 2 mm mercury. 

              The particle emitter 1 consists of an electron gun comprising a plate 10 and a cathode 11. 

              The cathode 11 is of molybdenum and has the very special form represented in Figs. 1 and 2.  It consists of a rim 11a connected by two aligned spokes 11b to a hub 11c pierced by a hole 11d with its axis along XX'.  The rim 11a is in two parts (as one sees in Fig. 1) which may be held together by screws (for example) forming a cavity of revolution 11e traversed by a number of holes 11f parallel to the axis XX' and regularly spaced.  The filament for heating, 12, situated in the interior of the cavity 11e and is connected to the power supply conductors 12a. 

              The best results are obtained with a cathode 11 of molybdenum.  The applicant has obtained satisfactory, but slightly inferior,  results with tungsten cathodes.  It turns out that molybdenum, and to a lesser degree