We were not long in discovering that headaches, both of the mildest and the severest types, might be accompanied either by a rush of blood to the head, with flushing of the skin, reddening of the eyes, and a bursting sense of oppression in the head, or, on the other hand, by an absolute draining of the whole floating surplus of the blood into the so-called "abdominal pool," the huge network of vessels supplying the digestive organs, which, when distended, will contain nearly two-thirds of the entire blood of the body, leaving the face blanched, the eyes white and staring, and the brain so nearly emptied of blood as to cause loss of consciousness or swooning. Other headaches, again, will be accompanied by a fresh, natural color and a perfectly normal and healthy distribution of the blood-supply. In short, the amount of blood in the head, whether plus or minus, has practically nothing to do with the pain, but depends solely upon the effect of the poisons producing it upon the heart and great blood-vessels. A good illustration of the full-blooded type of headache is that which so very frequently, indeed almost invariably, occurs in the early stage of a fever or other acute infection, such as typhoid, pneumonia, or blood-poisoning, Here the face is red, the eyes are bloodshot and abnormally bright, the pulse is rapid and full, the headache so severe as to become the first disabling symptom in the disease,--all because this is the effect of the poison (toxin) of the disease upon the heart, the temperature, and the surface blood-vessels. Fortunately for the sufferer, this head-pain, like most others in the course of severe infections, is only preliminary, for as soon as the tissues of the body have become thoroughly saturated with the toxins, the nerves become dulled and semi-narcotized, so that they no longer respond with the pain-cry. As the patient settles down into the depression and dullness of the regular course of the fever, the headache usually subsides into little more than a sense of heaviness, or oppression and vague discomfort. Moral: It is a sign of health to be able to feel a headache, an indication that your body is still fighting vigorously against the enemy, whether traitor within or foe without. On the other hand, many of our most agonizing, and particularly our most persistent and obstinate headaches, occur in individuals who are markedly anaemic, with a low, weak pulse, poor circulation, blanched lips, and dull, lackluster eyes. The one and only thing in common between these two classes of "head-achers" is that their blood and tissues are loaded with poisons. Whether produced by invading germs or by starvation and malnutrition of the body-tissues makes no difference to the headache nerves. Their business, like good watchdogs, is to bark every time they smell danger of any sort, whether it be bears or book-agents. One of the most valuable services rendered us by our priceless heads is aching.