During the four hundred years coffee has been recognized in the western world as a popular beverage, its power to control the minds and palates of its devotees has constantly increased. Its immense popularity as a world-beverage has not its basis in its taste, however, as is the case of sugar, nor in the cerebral intoxication with its unreasoning and unreal functional exuberancy, as that of alcohol; but in the energies generated in the bean itself, and imparted to the system in the form of muscular and vascular release. Hence the vital difference in the effects on the body, between alcohol and coffee, lies in the fact that in the former case the system has to pay for its over stimulation, but in the latter - if rightly enjoyed - the bean itself pays for the expense. This accounts for the weakening, exhausting reactions of the whisky stimulations, unknown to the "cup that cheers but not intoxicates."
The effect of coffee on the system, however, is largely determined by the conditions under which it is prepared and enjoyed. Suspended in the bean is found a volatile substance - the empyreumatic oil - which gives taste and aroma to the coffee, and at the same time exerts a reducing and modifying influence over the stimulating power contained in its twin-principle - the caffeine. Taken together, these two elements, hold in a safe balance the stimulating and invigorating impulse contained in the coffee bean.
But this fine adjustment is available only when the coffee has a truly hygienic preparation. Exposed to boiling, the caffeine decomposes into an acid - caffeic acid - which through the empyreumatic oil breaks down into an alkaloid. This changes the entire character of the coffee, which, from a bracing, self generative invigorant, is turned into a nerve-lashing, exhaustive stimulant, in which the adjustment or balance between the stimulating and regenerative powers of the bean has been destroyed. Hence coffee should be zealously guarded from the boiling pot, and should be prepared solely by the process of infusion through steaming, or the percolating process.
But apart from these constitutional qualities of coffee there are other conditions connected with its use, of which the coffee-drinking public cannot afford to be in ignorance. Barring a mere trace of nitrogen, the coffee bean contains no element of nutrition - con sequently is not a food - and must, therefore, remain classed as a systemic stimulant. For an element which has no cell-building power, has not the vital or physiologic legitimacy in the system held by food, and hence should not share the regularity of the latter as a means of replenishment.
Coffee is a remedy - a medicinal agent - introduced by nature in the service of man, under conditions when his system demands it. Furthermore, as a tropical plant, its sphere of virtue must naturally and evolutionally be connected with environmental influences. This will readily be seen when we recognize that the circulation of the system in general is under the influence of the quality of pressure received respectively from without and from within the organism - from without, in the low temperature of the atmosphere assisting the blood from the circumference to the center - and again from within, by the pumping action of the heart, forcing the blood from the center back to the circumference. In the tropics, however, where the temperature is higher outside than inside the body - the blood in its course from the periphery would be assisted in its exchange if an agent of expediency were introduced as a modifying force in the organism. Such an agent we find in the high percentage of quick combustible sugar in the tropical fruit; in the high stimulant of the native spices, and in the re-invigorating principle contained in the coffee bean. In other words, coffee by its power to stimulate the innervation of the central vessels and tissues, and thus direct the blood-stream center-ward, accomplishes the same result from within the organism, as the lower temperature of the temperate zone does from without.
This makes of coffee a tropical beverage, not only genetically but also conditionally and qualitatively. But as on the other hand each individual is a world in himself, with needs and necessities all his own, we may expect to find in the general temperament of man, such tendencies and characteristics which may demand for their modification and adjustment the same expediency which is represented by coffee in the tropics. Hence, as an occasional nerve stimulant and temperamental adjuster, coffee may be enjoyed even in the temperate zone by those whose temperament is subdued, and whose nervous exchanges are under control. By the high-strung, highly organized and nervously poised individual, coffee should not be used.
Moreover, in the philosophy of nutrition there is a principle which should never be lost sight of - that the only stimulant which can be safely enjoyed as part of our daily menu, is the stimulant contained in the food itself. As an integral part of its nature, every foodstuff contains a stimulant, so poised and adjusted that it imparts a natural impulse of power to the processes of digestion and assimilation. Divorced from this combination, the stimulant becomes a mere lash or irritant, which has needs and uses only as expediency, when environments and conditions make such adjustments necessary.
For those, whose temperaments permit the use of coffee, no admixture of sugar and cream should be allowed to interfere with its virtue. Cream especially perverts the nature of coffee by reducing its empyreumatic oil into a tannic acid compound - at once indigestible and toxic, giving rise to the formation of bile acids in the liver, with the subsequent appearance of a muddy complexion - due to bile pigments deposited in the skin. Another precaution of no less importance to the safe enjoyment of coffee is its temperature. From strong physiological reasons no beverage should be permitted to enter the system at a higher temperature than blood heat, and it may be safely said that the greater injury wrought by the consumption of coffee lies in its admixtures and temperature, rather than in native disqualifications.