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LEFT RADIOPHONE 411 BADIX instrument is inclosed in a glass globe from which the air has been exhausted, so that no heat is transmitted. When the disks are exposed to light, revolution begins and its speed is governed by the intensity of the light. Two candles pro- duce twice the effect of one, and the flame of magnesium wire makes the disks spin with great rapidity. RADIOPHONE, a word that applies to any invention that transmits or pro- duces sound by means of radiant energy, particularly a device similar to the photo- phone, whose receiver is a block of vul- canite, with no telephone, the vibratory contraction and expansion being pro- duced by the heat of the beam while vibrating, which is accompanied by an audible sound. RADISH, the Raphaniis sativus, the garden radish. It was cultivated in an- cient times in India, whence it found its way to Europe and the United States. RADIUM, an element recently dis- covered combined with polonium. Radi- um was discovered in 1903 by M. and Mme. Curie of Paris. It is worth from $100,000 to $200,000 an ounce. It throws out heat, light, and energy with- out loss of intensity, and without waste or diminution. Its principal practical use thus far has been in medical science for cure of cancer and restoration of eyesight. RADIUM THERAPY, the use of radium for the cure of disease. It is still in the experimental stage, but suf- ficient success has already been gained to indicate that it may prove of great value in connection with certain malig- nant growths. The rays are applied by various methods: in some cases a tiny emanator tube is buried in the growth, in others the emanation is condensed in vaseline, oil, glycerine, or water and ap- plied externally; or, again, the rays are condensed on arsenic, bismuth or quinine and taken internally. Another method of external application is to coat linen, or copper plates with a varnish contain- ing radioactive salts, these being ap- plied to the affected parts, the surround- ing flesh protected with lead foil. It is sometimes found that treatment with the rays will produce temporary improvement, but that complete cure does not take place. This is particularly the case with epitheliomas oi the mouth and pharynx and laryngeal mucous mem- branes. Considerable success has been obtained in treating cancer of the uterus. After prolonged treatment amounting to as much as 60 hours spread over a pe- riod of five to ten days, there has followed a decrease in pain, the arrest of hemor- rhage and discharge, and a healing of ulcerations. Similar success has at- tended treatment of carcinoma of the rectum, and cancer of the breast. In some instances of the latter, there has been apparently complete cure, and in the case of rodent ulcer apparent cure has resulted from a single treatment. In a report made by the Radium Insti- tute of London (1917) it is stated that of 169 cases of rodent ulcer, 122 were cured and 37 were improved. Favor- able results are also reported in the treatment of lympho sarcoma, in many cases the growth steadily shrinking and finally disappearing completely, while some success has been obtained with fibroid disease of the uterus, lupus vul- garus and pruritis arthritis. A method of treatment developed in the United States has given good results in the treatment of cancer of the bladder and prostate. A gold needle, four to six inches long, containing radium in the point, is thrust into the center of the growth, and left there for some hours, local anaesthetics being used to deaden the pain of application. In nearly all cases after such applications there is a period of reaction which may last sev- eral months. Birthmarks and scars have been beneficially treated by radium emanations. It must, however, be em- phasized that in spite of much real or apparent success, radium therapy is in its early stages and there is a general agree- ment that the only reliable treatment for malignant grouiihs is removal by opera- tion, and that treatment by radium should only be resorted to in those cases where surgical operation is impossible or inadvisable. RADIUS, in anatomy, the outer of the two bones of the forearm. In botany, and plural form, the peduncles support- ing the partial umbels in an umbellifer. In fortification, a line drawn from the center of the polygon to the end of the outer side. In geometry, the distance from the center of a circle to any point of the circumference. RADIUS VECTOR, in astronomy, an imaginary line joining the center of a heavenly body to that of any second one revolving around it. In geometry, a straight line, or the length of such line, connecting any point, as of a curve, with a fixed point or pole, round which it re- solves, and to which it serves to refer the successive points of a curve in a system of polar co-ordinates. RADIX, in algebra, the root of a finite expression from which a series is derived. In anatomy, the root or portion of anything inserted into another, as the root of a tooth. In botany, the root