The _tendons_ inserted into the enlarged bones have been found proportionately over-developed. The _muscles_, however, are seldom hypertrophied, and occasionally, as in Busch’s case, they may undergo an atrophy secondary to the impaired mobility of the joint. In a case of von Fischer’s, muscular hypertrophy was demonstrated, but no evidence of increased power was present; and, judging by the comparative disuse of the limb, it is probable that the strength was lessened. The muscular power is, as a rule, so far augmented in response to functional necessity that the enlarged part may be used without more sense of effort than that which accompanies the same actions on the normal side, as in Wagner’s case (_l.c._), in which the hand weighed about twelve pounds and yet could be moved with perfect ease; there is seldom, however, any such absolute increase of strength as would indicate a genuine muscular hypertrophy. The _arteries_ in all the instances of false hypertrophy, with the exception of Reid’s[40] cases, were of ordinary size and apparently not enlarged in proportion to the gigantic development of the part to be nourished. This is a fact of considerable pathological significance. The _veins_ and _capillaries_, unlike the arteries, appear especially liable to change. Varicosities of the veins are very common, and in some cases great thickening of the walls may be superadded (Busch, _l.c._). In Dr. Finlayson’s case the cutaneous vessels over the enlarged parts and in patches over the trunk became enlarged when the child cried, but subsided during quiescence. In Wagner’s case the fingers of the hypertrophied hand were said to become as red as a “Blutschwamm” when the member hung down, the arteries being nevertheless of normal size. Angiectases and angiomata are frequently seen. Capillary nævi of enormous extent sometimes co-exist (as in Adams’s case, in which the whole lower extremity and buttock were involved), and are usually, but not invariably, confined to the hypertrophied parts. The _lymphatics_ are liable to dilatation, and may form diffuse swellings or soft tumours of considerable extent. The glands, however, are never affected. The _nerves_ appear to be normal. The condition of the nerve centres has not yet been investigated except in a case of Eve’s, in which the lateral asymmetry of the head and face extended to the brain.