Poor diet no doubt is the real cause of this condition, and a great proportion of the inhabitants, as is well known, of these two countries subsist principally on food, not only non-nutritious, but impure in the extreme, which being coupled with the fact of habitual abstention from salt, brings about, as I have said before, a condition of things very favourable for the reception, generation, and development of parasitical organisms. The outbreak which occurred in the St. Gothard tunnel originated from the impurity of the food with which the workmen were supplied, and the absence of salt, could we but fathom the real truth of the matter, though we must not lose sight of the fact that the surroundings were every way calculated to facilitate the growth of disease. The medicinal properties of mineral waters are of great value in some conditions of the system, especially those resulting from high living and when associated with habitual indulgence in those alcoholic beverages which tend to cause congestion of the liver. These people are not what one would designate as intemperate, but whose partial physical prostration and irregularity of the secretions have been brought about by luxurious living and the unnecessary use of stimulants, combined with unhealthful indolence, and other pernicious habits, which are considered to be of the highest importance by those unhappy votaries of fashion. Thousands of patients, and many who fancy that they are such, flock to those localities which are famous for their mineral waters; thousands go and thousands return, some better, some worse, and some in the same state of health as when they started: all declare that they are better for their trip, and it may be only a few are acquainted with the constituents of the water they have been drinking; many, if they knew that they are all derived from rock-salt, and that the other constituents to which their curative powers are ascribed are only added as the brine ascends to the surface, would be not a little amazed at their inconsistencies: to refuse to eat salt at meal-time because it is supposed to be deleterious, and then to drink, it may be, tumblerfuls of the solution, is somewhat curious. As all mineral waters originate from rock-salt, and as they all owe their other constituents to superincumbent strata, it would not be unreasonable to suggest that the chloride of sodium is, _prima facie_, their principal ingredient, and that their beneficial effects are to a certain extent due to it, more than to the presence of those from which their names are derived; though of course there is no denying the fact that some mineral waters are more suitable for some constitutions than others. One would not advise individuals of plethoric habits to drink those waters which are termed chalybeate, nor those whose kidneys are affected to drink acidulous or carbonated waters; we should recommend quite the reverse.