Although the so-called actinic rays have curative value in certain cases, there are some instances where light-baths are claimed to be harmful.  It is said that sun-baths to the naked body are not so popular as they were formerly, except for obesity, gout, rheumatism, and sluggish metabolism, because it is felt that the shorter ultra-violet rays may be harmful.  These rays are said to increase the pulse, respiration, temperature, and blood-pressure and may even start hemorrhages and in excessive amounts cause headache, palpitation, insomnia, and anemia.  These same authorities condemn sun-baths to the naked body of the tuberculous, claiming that any cures effected are consummated despite the injury done by the energy of short wave-length.  There is no doubt that these rays are beneficial in local lesions, but it is believed that the cure is due to the irritation caused by the rays and the consequent bactericidal action of the increased flow of serum, and not to any direct beneficial result on the tissue-cells.  Others claim to cure tuberculosis by means of powerful quartz mercury-arcs equipped with a glass which absorbs the ultra-violet rays of shorter wave-lengths.  These conclusions by a few authorities are submitted for what they are worth and to show that this phase of light-therapy is also unsettled.

Any one who has been in touch with light-therapy in a scientific role is bound to note that much ignorance is displayed in the use of light in this manner.  In fact, it appears safe to state that light-therapy often smacks of quackery.  Very mysterious effects are sometimes attributed to radiant energy, which occasionally border upon superstition.  Nevertheless, this kind of energy has value, and notwithstanding the chaos which still exists, it is of interest to note some of the equipment which has been used.  Some practitioners have great confidence in the electric bath, and elaborate light-baths have been devised.  In the earlier years of this kind of treatment the electric arc was conspicuous.  Electrodes of carbon, carbon and iron, and iron have been used when intense ultra-violet rays were desired.  The quartz mercury-arc of later years supplies this need admirably.  Dr. Cleaves, after many years of experience with the electric-arc bath, has stated: 

From the administration of an electric-arc bath there is obtained an action upon the skin, the patient experiences a pleasant and slightly prickly sensation.  There is produced, even from a short exposure, upon the skin of some patients a slight erythema, while with others there is but little such effect even from long exposures.  The face assumes a normal rosy coloring and an appearance of refreshment and repose on emerging from the bath is always observed.  From the administration of the electric-arc bath there is also noted the establishment of circulatory changes with a uniform regulation of the heart’s action, as evidenced by improved volume and slower pulse rate, the augmentation