logy to know what fatigue really means. A muscle which is tired out is different chemically from the same muscle in its more normal condition, when it is ready to respond vigorously to ordinary stimuli. It has lost something, and is, besides, over-charged (poisoned, in fact) with the products of its own activity, and it can only be restored by a fresh supply of the material which it requires, and the carrying away of the poisonous waste products. Fatigue of nerve centres is no doubt strictly analogous to fatigue of muscles.
"It is practically impossible for us, by voluntary exertion, to reach the degree of absolute fatigue, which the physiologist produces by electric stimulation of a nerve-muscle preparation. The sense of fatigue becomes so intense that voluntary effort cannot overcome it. So no man can produce asphyxia by simply holding his breath, because the besoin de respirer becomes irresistible; but it is quite possible for a narcotic to so dull the sensory part of the respiratory reflex mechanism as to permit asphyxia to take place.
"The sense of fatigue, and the besoin de respirer are both Nature's danger signals. Drugs which hide such signals from us are a more than doubtful benefit. If it were possible for us to suppose that a fraction of a grain of cocaine could afford to exhausted nerve centres, and muscles, the nutriment which they require for their restoration, and at the same time eliminate the poisonous waste products, then it would be reasonable to prescribe the drug for use by all who are overworked, and perhaps suffering from the malnutrition consequent upon, 'nervous dyspepsia,' as well as mere want of rest.
"In this go-ahead century it is no wonder that many are but too ready to experiment with a drug which professes to be able to remove fatigue, and to enable a man to go on working when, without its aid, weariness had become unendurable. Cocaine claims all this; and it is most dangerous just because, for a time, it seems able to keep its promise. That is how victims to cocainism are made. Let us be honest with our overworked