The entire matter resolves itself into one of individual tolerance, resistivity, and constitution. Numerous examples of young abstainers who have died and coffee drinkers who have still lived on can be found, and _vice versa_, the preponderance of instances being in neither direction. Bodies of persons killed by accident have been painstakingly examined for physiological changes attributable to coffee; but no difference between those of coffee and of non-coffee drinkers (ascertained by careful investigation of their life history) could be discerned.[216] In the long run, it is safe to say that the effect of coffee drinking upon the prolongation or shortening of life is neutral. _Coffee in the Alimentary Tract_ When coffee is taken _per os_ it passes directly to the stomach, where its sole immediate action is to dilute the previous contents, just as other ingested liquids do. Eventually the caffein content is absorbed by the system, and from thence on a stimulation is apparent. Considerable conjecture has occurred over the difference in the effects of tea and coffee, the most feasible explanation advanced being one appearing in the London _Lancet_.[217] The caffein tannate of tea is precipitated by weak acids, and the presumption is that it is precipitated by the gastric juice and, therefore, the caffein is probably not absorbed until it reaches the alkaline alimentary tract. In the case of coffee, however, in whatever form the caffein may be present, it is soluble in both alkaline and acid fluids, and, therefore, the absorption of the alkaloid probably takes place in the stomach. This theory, if true, goes far toward explaining the more rapid stimulation of coffee.