We return to that part of the museum where we can study the growth of the human skeleton. Before us there are arranged specimens, row upon row, showing the development of the bones of the child before birth. It will be better, however, to confine our attention to one bone, and we select the femur or thighbone, because by watching the manner in which it is formed and increased in length, a guide will be given us to the way in which we attain to our adult height. Up to the seventh week, when the human foetus is less than an inch in length, the thigh-bone is formed of cartilage; there then appears in the cartilagenous shaft a centre of bone formation, and the cartilage is gradually replaced by bone until only its extremities remain as cartilage. At the end of the ninth month the child is born, being then about twenty inches long, and seven lbs. in weight. In the skeletons showing the condition just before birth, we see that a separate centre of bone formation has appeared in the cartilage at the lower end of the femur, in those showing the skeleton of the child some months after birth we note a centre has also appeared in the cartilaginous head at the upper end of the femur. Passing on to the skeletons which show the condition in the eighth year we see that the ends of the bones are represented by separate parts or epiphyses, each of which is fixed to the shaft by a plate of cartilage. These plates of cartilage which join the epiphyses to the shaft are seats of most active formation of bone ; the new bone laid down at these lines causes the femur to increase in length. On the surface of the femur also new bone is being laid down and thus the thigh-bone increases in thickness. These lines of growth—epiphyseal lines they are called—keep open so long as growth in stature continues; when, however, they become closed growth in height is over. Hence in the skeletons of women who have died about the age of twenty, and in those of men at the age of twenty-four, we find that most of the growth lines are closed. There is, however, a considerable degree of variation as regards the date of closure, for we know some men who grew very little after their twentieth year, and others who kept on adding to their stature until they were twenty-six or even older.

What causes these lines of growth to close at a definite period of life and prevents them from ever again becoming opened is still a mystery. There are two celebrated skeletons in an adjoining case of this museum which throw some light on the circumstances which determine growth and stature. These two skeletons are placed side by side. One is that of Charles Byrne, who was exhibited in London as " O'Brian the Irish Giant " and died in 1783 at the age of twenty-two. The skeleton has a height of seven feet eight and two-fifths of an inch (2,358 mm.). It towers above the skeleton of Caroline Crachami, "the Sicilian dwarf," who was also exhibited in London and died at the age of nine. Her skeleton is little bigger than that of a newly born child; it is only twenty inches high, whereas, if growth had been normal, she should have measured about forty-eight inches at the age of nine. The giant on the other hand is twenty-four inches taller than theaverage man. If we could discover what caused arrest of development in the one, and over-development in the other, we should be in a fair way to solving the mystery of growth. Towards the end of the nineteenth century it was discovered that giants of the type of O'Brian were really the subjects of disease; in all of them the small pituitary gland, which lies in the base of the skull under the brain, is the seat of an overgrowth, often of a tumour. In some manner an increase or alteration of the secretion of the pituitary gland, which passes into the circulation, acts upon the growing lines of the bones and stimulates them so that the bones increase in length at a rapid rate, thus producing the condition known as giantism. The increased growth is apparently due to an increase in the amount of pituitary secretion. The muscles and other neighbouring parts are similarly affected and grow at a corresponding rate. We infer then that one of the circumstances which regulates growth is the secretion of the pituitary gland. It seems within the bounds of possibility that we may yet be able to add even a cubit to the stature if we should so wish. Near by is the skeleton of an unfortunate man who was the subject of a disease of the pituitary gland ; the gland had become enormously enlarged during adult life and after the growing lines of the bones had become closed. A cast of his face shows how massive and ugly the face has become; lips are thickened ; the ridges over the orbits form great bulging masses which overshadow the eyes ; the nose and face are really gigantic. His hands and feet are enlarged and overgrown. The backbone, abnormally curved, is much longer than is usual, while the chest is huge and barrel-shaped. All these changes occurred slowly, after the man was fully grown, and completely changed his outward appearance and his nature. We suppose that if the growth lines had still been open when the disease set in he would have become of great stature. The man was the subject of a disease of growth which we name acromegaly, and which we believe to be due primarily to an enlargement or tumour of the pituitary gland. In all of these cases the pituitary is enlarged.

In the skeleton of little Caroline Crachami we see the result of an opposite disease, but its exact nature we do not yet know. Instead of being about forty-eight inches high as the skeleton of a child of nine should be, it is only twenty inches. The bones, too, have scarcely passed beyond the stage reached in the skeleton of a child at birth ; there has been a complete arrest of growth. It is possible that the condition may result from a deficiency of secretion from the pituitary gland, but there are grounds for suspecting that another gland which supplies an internal secretion is also at fault—namely the thyroid, which we have already seen in the neck. Many of the dwarfs who have figured in history and in fable have suffered from the same disease as Cra-chami. The famous dwarf, Jeffrey Hudson, a favourite at the Court of Charles I., was one of these. Even as a young man he was no taller than Crachami, and was served up in a pie at the table of the Duke of Buckingham as a surprise for the Queen of Charles I., to whom he became an engaging and sharp-witted little page. At a later stage of his manhood growth set in and he became forty-two inches in height by his thirtieth year. We see then that growth may be delayed until a late period in life.