Each nasal chamber is lined by a mucous membrane called the _pituitary_ or _Schneiderian_. This membrane is prolonged into the meatuses and air sinuses which open into the nasal chambers. The _pituitary_ membrane is thick and soft and diminishes the size of the meatuses and air sinuses. It is covered by a ciliated columnar epithelium and contains numerous racemose glands for the secretion of mucous or _pituita_. It is also vascular and the veins which ramify it have a plexiform or net-work like arrangement. It divides into two membranes--a respiratory, which is concerned in breathing, and an olfactory region. The respiratory region corresponds to the floor of the nose, to the inferior turbinated bone and to the lower third of the nasal septum. The olfactory region is the seat and distribution of the olfactory nerve and corresponds to the base of the nose, to the superior and middle turbinals and the upper two-thirds of the nasal septum. Recent developments prove that this gland has a profound influence over the animal economy. It is believed by some that the _pituitary body_ actually destroys certain substances which have a toxic influence on the nervous system; others believe that it secretes material media for the proper action of the trophic or nutritive apparatus; still others believe that it influences blood-pressure. It is known, however, from experimentation, that its removal in dogs, cats, mice and guinea pigs causes a fall of temperature, lassitude, muscular twitchings, dyspnoea or difficult breathing, and even speedy death. Hypertrophy of the gland is directly associated with certain diseases, such as _giantism_ and _acromegaly_. The latter is a disease which causes a general enlargement of the bones of the head, feet and hands, usually occurring between the ages of twenty and forty years, and most frequently in females. The fact that these diseases are so closely associated with a hypertrophic condition of the pituitary gland has led to the conclusion that perhaps the giants or Cyclops of ancient times were cases of _giantism_ or _acromegaly_. This view, while interesting from the standpoint of the functions of the _pituitary_ gland, is not necessarily a correct one; for the age of giants, when men attained to a much larger stature than at present, can be accounted for on other grounds, namely; that the early mesozoic man, on account of his having to live among animals, trees and other vegetation of such huge size, had naturally to be fitted with a frame proportional to other animals in order that he might successfully cope with his environing conditions. Nature thus wisely fitted him for the conditions which she had prepared for the scenes of his life.