Here in their every movement the entire existence of living beings becomes a _laying hold of the external world_--a gross laying hold with hands and teeth as well as that subtle _mental_ laying hold which we generally denominate “comprehension.” As the whole existence of a flame is a laying hold of the external world, as it subsists solely by reason of this prehensile activity, even so is it with the _I_-process. Buddhist psychology distinguishes between four varieties of aliment. First, there is aliment in the common, vulgar sense of the word, be it in gross growth-promoting form as solid or liquid food, be it in fine growth-promoting form as respiration. Second, contact, as the mutual encounter of the senses and their corresponding objects. Third, mental apprehension; and fourth, consciousness; these two latter being the working up, the assimilating of what issues from contact. From the commanding height of the position which Buddhist thinking takes up towards the process of life, it cannot possibly encounter that “problem” with which scientific physiology finds itself forced to wrestle. Briefly stated, that problem runs as follows:-- “How can it ever be possible for a living being to appropriate something to itself, assimilate something, take up something into itself, whether this ‘something’ be of the gross growth-promoting variety--nourishment in the vulgar sense of the word--or of the intellectual sort, as sense impressions and the content of consciousness?” There was a time in the history of natural science, more particularly in the history of the healing art--and that time is hardly past yet; we still stand within its fringes--when to work at all with the concept of a “vital energy” was regarded as synonymous with being unscientific, indeed, was esteemed mere blind faith. At every opportunity, seasonable and unseasonable, it was declared that “to-day” we had no longer any need of a “vital energy,” that the mechanical view explained all that very much better; yet, in actual truth, one only showed how wanting one was in the sense of actuality when one could accept as satisfactory a “reading” of life which presented it under the figure of endosmotic and diosmotic processes, and such like. Here, however, is abundantly proved true that saying of Horace that nature is something which man cannot drag out even with a pitchfork; and it was with a pitchfork of the biggest sort that the mechanists took the field against actual life. To-day the antithesis of the mechanical view--the teleological--has found its way back into medical thought, and begins again to move about naturally and without restraint in the domain of therapeutics. Beyond all else, it was the progress made in physiological chemistry, the peculiar, seemingly inexplicable facts here observed, which perforce impelled towards this inversion of positions.