Defective circulation of the blood to the feet can not only result in cold feet, but also in very serious ailments, and even in a shortening of the ordinary span of life. Thus, in consequence of a deficient influx of arterial blood and the stagnation of the venous circulation, especially in old people with sclerotic changes of the blood-vessels, a very trying and long-continued ulceration of the feet may result. By bringing more arterial blood to the feet and causing hyperæmia, according to Bier, we can cure this condition. Still more serious consequences may be brought about by defective circulation in the feet, and especially in the toes, in the form of senile gangrene, which is far more frequently found in diabetic persons, and sometimes even before the commencement of old age. In cases of arteriosclerosis, where cold feet are the consequence of defective blood-supply owing to arterial degeneration, iodides together with thyroid extracts will be found successful. They produce a dilation of the blood-vessels, diminish the viscosity of the blood, and thus produce the sensation of heat. The method of application will be found in the chapter on the treatment of old age by organic extracts. As the promotion of a hygienic condition is an excellent preventative against cold feet and also excellent for their treatment we repeat again that a foot-bath should be used daily in such cases, and not only warm, but also cold water should be used therein. Cold water acts as already mentioned as a stimulant when applied as a foot-bath; but it should only be used for a very short time, after which energetic rubbing of the feet will produce active circulation and the feeling of warmth in them. We recommend for cold feet to rub them with a cold wet towel, then to pour over them a little eau de cologne or alcohol, and again rub them till they begin to become red; we must next move the toes forward and backward twenty or thirty times with our hand. We will then feel in the feet a sensation of agreeable warmth. ------------------------------------------------------------------------ CHAPTER XXX. ON THE BENEFITS OF SUNLIGHT. IT is a matter of everyday observation that when we leave plants in a room, where no sunshine can penetrate, they lose their color and soon show quantities of parasites. Similar changes occur in persons who live in dark rooms and seldom come into the sunlight. They become pale, and are liable to all kinds of bacillary infections, especially tuberculosis. An Italian proverb says, very justly, “Dove no viene il sole viene il medico”—“Where comes no sun, the physician is coming,” and a German proverb again says, “Auf die schattige seite der strasse kommt der Leichenwagen doppelt so oft, als auf die sonnige,” which means in English, “The funeral coach turns twice as often on the shady side of the street as on the sunny side,” which saying, like most proverbs, contains much truth.