In addition, allusion should be made to Dana’s symptom--‘cerebellar fits’--said to be almost pathognomonic of an extra-cerebellar tumour (or abscess) situated in the cerebello-pontine angle. In such cases, there may be sudden attacks of tinnitus, vertigo, and apparent loss of consciousness, during which the patient falls to the ground as if struck with lightning. The final stage of falling is said to be dependent, not so much on actual loss of consciousness, as from the absence of cerebellar innervation and a total loss of equilibrium. These attacks are brought about by sudden alterations in position. (_G_) =To the pituitary region.= Considerable research has recently been carried out, and much knowledge obtained as to the functions of the pituitary body and the symptoms that result from lesions of the gland.[44] As is well known, the pituitary body consists of two portions, an anterior (derived from upgrowth of buccal epiblast) and a posterior (formed from neural epiblastic downgrowth). Complete removal of the body in animals invariably terminates fatally, the patient exhibiting a definite train of symptoms--cachexia hypophyseopriva--and dying within a few days or weeks, the younger animals living longer than the older. The symptoms of apituitarism are as follows: fall of body temperature, lowering of blood-pressure, increasing feebleness, muscular tremors, a curious attitude resembling that of defæcation, coma, and death. On further investigation it was proved that all these symptoms were observed when the anterior portion of the gland was alone removed, whilst, on the other hand, extirpation of the posterior half created no great change in the animal’s general health. [Illustration: FIG. 70. A PITUITARY TUMOUR.] In the human being it would appear that the symptoms resulting from the development of pituitary tumour formation may be classified into two groups, those of hyper-pituitarism and those of hypo-pituitarism. In the former case the secretion being superabundant, acromegaly and giantism are observed. Keith[45] considers that one of the substances secreted by the gland is of the nature of a hormone, rendering the osteoblasts hypersensitive to the various stresses that fall upon the human skeleton during life, and that the osteoblasts, at the origins and insertions of muscles, become increasingly sensitive to the traction of muscles. Muscular impressions and processes of the skeleton become exaggerated by the new bony matter, and if the epiphyseal lines be still open, the osteoblasts of which appear to be specially affected, giantism is produced. The skull and skeleton of the giant O’Brien are regarded as typical examples of the results due to over-secretion of the gland.