Among the most striking manifestations arising from arrest of development in certain directions with possible hypertrophy in others, are the conditions known as giantism and dwarfism (_see_ Frontispiece). Both these conditions may be expressions of atavism to no very remote ancestors and present little if any evidences of degeneracy. In other cases degeneracy may be well marked, and the condition be due to imperfect gland action, such as disorder of the pituitary body, which causes very frequently an enlargement of many of the bones of the body, and very often a uniform enlargement of all the bones. Indeed, as Marie has said, giantism is acromegaly occurring during the period of adolescence. In many instances the opposite condition, dwarfism, occurs during infancy from causes which check the further growth of the body, although the general functions remain unchanged. Dwarfism is very apt to be attended by preservation of the intellectual faculties without evidence of degeneracy, other than the egotism shown in extreme vanity. Moral defects are, however, more apt to occur in dwarfism than in giantism, in which last condition mental defect is apt to occur, varying from a simple good-humoured stupidity to feeble-mindedness. In proportion as the central nervous system has been affected will the stigmata of degeneracy appear in both conditions. As the line between disease and disordered function is not thinly drawn in these cases, disorders like rickets or local bony tendencies to extensive growth may coexist with both conditions. Infantilism is peculiarly apt to occur with giantism, and while less frequent in dwarfism it also occurs, but is then especially apt to be associated with rickets. Closely akin to these conditions are leontiasis ossium and acromegaly, both of which are characterised by similar trophoneurotic defects. The first of these conditions may occur precedent to puberty and cease in its completion. Kiernan has observed this in the case of an imbecile on Ward's Island, who lived until the age of 75, after spending more than sixty years in the charitable institutions of New York. His ancestry was of the criminal and defective classes. Acromegaly is characterised by abnormal growth, chiefly in the bones of the head, face, and extremities. As a rule, the disorder begins at the completion of puberty, although it occasionally occurs at the onset of the climacteric. The illustration given (Fig. 104) presents the characteristic features of the disease. In this case there are local evidences of congenital defect. The prevailing trend of opinion is that this condition is due to irregular action of the pituitary body which controls osseous development. [Illustration: FIG. 105.]