Japan, the land of volcanoes and earthquakes, is naturally rich in mineral springs: and the Japanese, with their passion for bathing, make the fullest use of them. The most noted of the many hundreds of Japanese spas are:-for sulphur baths, Kusatsu, Ashinoyu, Yumoto near Nikkō, Nasu, Shiobara, and Unzen near Nagasaki; for iron baths, Ikao, Arima, and Beppu; for salt baths, Atami and Isobe. Miyanoshita, one of those bestknown to foreigners, has only traces of salt and soda. Its waters may therefore be used without medical advice, simply for pleasure's sake. There are powerful iron and sulphur springs at Ōji goku (lit. "big hell"), some four miles beyond Miyanoshita. The crater of Shirane-san in the province of Kōtsuke has a pool so rich in hydrochloric acid (2 1/2 per cent. according to Dr. Divers, F.R.S.), that it may be administered as an excellent lemonade in the treatment of stomach and other affections. But speaking generally, sulphur, iron sulphate, and salt are everywhere the chief minerals found in the Japanese springs. Excepting the Hirano water used for Seltzer, very few contain carbonic acid gas. Few are cold; few are efficacious, like Vichy and Karlsbad, in diseases of the stomach and liver. On the other hand, the Kusatsu waters probably stand alone in the world by reason of their double character, consisting, as they do, of cold corrosively acid water and nearly boiling sulphur water. Little short of miraculous are the cures which, by virtue of their temperature and their mineral acids, sulphur, and arsenic, they are capable of working, when mixed, upon syphilitic persons and on those afflicted with the severer forms of rheumatism. The Japanese have a proverb to the effect that love is the only grave distemper against which Kusatsu can effect nothing.
In many cases a spring is famous in its own neighbourhood only. But it then almost invariably gains in one way what it loses in another. The good country folk for twenty miles around consider it a panacea for all the ills to which flesh is heir. It is impossible to picture to oneself anything more grotesquely dissimilar to an Ems or a Homburg than one of these tiny spas, perched- say-amidst the mountains of Shinshū or Etchū, and visited only by Japanese of the most old-fashioned type and limited means- where, instead of a table d'hôte, each guest is served in his own poor room with a bowl of rice or maybe millet, a scrap of salted egg-plant, and perhaps, on high days and holidays, a small broiled fish. Even this is luxury compared with the state of things existing in some remote districts, where the peasant invalids come bringing their own rice and bedding with them on packhorses, and pay only five cents a day for lodging, for the use of the mineral spring, and a titbit or two at each meal to help the rice down.
In opposition to all European sanitary ideas, the mineral springs of Japan are used at very high temperatures. Invalids enter baths of from 110° to 115° Fahrenheit, and their healthy friends go in with them for the sake of killing time agreeably. At Kusatsu the temperature of the baths is higher still. It ranges from 120° to 130° Fahrenheit; and as the first effect of the waters is to bring out sores all over the body, even if there were none before, the sufferings of those condemned to "make a cure" may be imagined. So excruciating is the agony that experience has dictated a peculiar device for meeting it:-the bathers are subjected to military discipline. The squad of unfortunates approaches the bath to the sound of the trumpet, they wet their scalps and foreheads at another trumpet blast, in order to prevent a rush of blood to the head, and so on throughout the performance, notice being given to them of the passing of the minutes while they sit boiling, with a view to keeping up their courage by the knowledge that the ordeal will soon be over. The whole life at Kusatsu is so strange that he whose stomach is not easily upset by nasty sights would do well to go and inspect it. To squeamish persons we say most emphatically, "Keep away!"
Book recommended - Murray Handbook for Japan, passim.