Book 3
15
For, as was pointed out in the first book,I. x. things having a similar substance can easily change into one another, whereas it is impossible for those which are very different to be assimilated to one another without intermediate stages. Such a one in respect to cartilage is the myxoid substance which surrounds it, and in respect to ligaments, membranes, and nerves the viscous liquid dispersed inside them; for each of these consists of numerous fibres, which are homogeneousLit. homoeomerous, i.e. the same all through, of similar structure throughout, the elements of living matter. cf. p. 20, note 3, and cf. also the cell of Erasistratus, p. 153. — in fact, actual sensible elements; and in the intervals between these fibres is dispersed the humour most suited for nutrition; this they drawn from the blood in the veins, choosing the most appropriate possible, and now they are assimilating it step by step and changing it into their own substance.
