Some doctors have thought, on the contrary, that _excess_ of blood in the head was the cause, but results of treatment so directed did not bear out the sanguine hopes built on the theory. The fact that convulsions occur in diabetes and alcoholism, suggested that epilepsy was due to poisons circulating in the blood, and thus irritating the brain. Every act uses up cell material and leaves waste products, exactly as the production of steam uses up coal and leaves ashes. Various waste products have been found in more than normal quantities in the blood of epileptics, but it is uncertain whether accumulation of waste products causes the seizure. A convincing theory must satisfactorily account for all the widely diverse phenomena seen in epilepsy, and the problem must remain largely a matter of speculation, until research work has given us a far deeper insight into the biochemistry of both the brain cells, and the germ-plasm than we have at present. * * * * * CHAPTER V PREVENTION OF ATTACKS In health matters, prevention is nine points of the law. Some patients are obsessed by a peculiar sensation (the "aura") just before a fit. This warning takes many forms, the two most common being a "sinking" or feeling of distress in the stomach, and giddiness. The character of the aura is very variable--terror, excitement, numbness, tingling, irritability, twitching, a feeling of something passing up from the toes to the head, delusions of sight, smell, taste, or hearing (ringing, or buzzing, etc.), palpitation, throbbing in the head, an impulse to run or spin around--any of these may warn a victim that a fit is at hand. Some patients "lose themselves" and make curious mistakes in talking. The warning is nearly always the same each time with the same patient, and is more common in mild than in severe cases. Rarely, the attack does not go beyond this stage. When the patient becomes conscious of the aura he should sit in a large chair, or lie down on the floor, well away from fire, and from anything that can be capsized. He must never try to go upstairs to bed. Some one should draw the blind, as light is irritating. If the warning lasts some minutes, the patient should carry with him, a bottle of uncoated one-hundredth-grain tabloids of Nitroglycerin, replacing the screw cap with a cork, so that they can quickly be extracted. When the warning occurs, one--or two--should be taken, and the head bent forward. The arteries are dilated, the blood-pressure thus lowered, and the attack _may_ be averted. The use of nitroglycerin is based on the theory that seizures are caused by anaemia due to vasomotor constriction. Success is only occasional, but this is so welcome as to justify the habitual use of the method.