122 Herring 



be understood. Moreover, it appears that acromegaly may occur without 

 any apparent change in the pituitary, and that tumours of tlie pituitar}^ 

 are not always attended by acromegaly. A feature as constant as acro- 

 megaly in affections of the pituitary is the occurrence of polyuria with 

 or without sugar in the urine (Hansemann (16), Sternberg (41)). 



Oliver and Schafer (28) in 1895 described the presence of a substance 

 in saline extracts of the pituitary, which, when injected intravenously, 

 produces a rise of blood-pressure. Howell (18) showed that this sub- 

 stance is only present in the posterior lobe. Magnus and Schafer (24) 

 in 1901 noticed that intravenous injection of saline extract of the 

 posterior lobe is followed by a marked increase of urine flow. Schafer 

 and Herring (37) confirmed this observation, and showed the striking- 

 parallelism which exists between the suprarenal capsules and the pituitary 

 in development, structure, and functions. In each there are two parts, one 

 of which, a highly vascular epithelium, yields no active extract, while the 

 other, of neuro-ectodermic origin, gives an extract which has a remarkable 

 physiological effect upon the heart and arteries. The view was conjectured 

 that in the epithelial part of each organ the material which is to furnish 

 the active agent of the secretion passes through certain stages of formation, 

 and that its production is merely completed in the neuro-ectodermic part, 

 in which part alone the full activity of the secretion is acquired. That 

 the posterior lobe of the pituitary should furnish an active secretion is 

 difficult to reconcile with the usual views held on its structure. The older 

 anatomists, W. Miiller (27), Schwalbe (40), and Toldt (45), looked upon 

 it as a mass of connective tissue cells and flbres which during development 

 have destroyed all trace of the original nerve tissue. Berkley (2), on the 

 other hand, describes in it a complex arrangement of nerve cells and nerve 

 fibres, besides neuroglia and ependyma cells. Kolliker (19) takes up an 

 intermediate position, and believes that there are no true nerve cells, but 

 neuroglia and ependyma, a view similar to the one held by Virchow. 

 Peremeschko (30) first recognised that the posterior lobe has an epithelial 

 investment. Osborne and Swale Vincent (29) state that extracts of 

 the central part of the posterior lobe are more active than extracts of 

 the margin of the lobe, and believe that the epithelial investment would 

 be found to be inactive if it could be properly isolated. 



The pituitary body is found in all vertebrates, and, although differing 

 widely in structure and in the arrangement of its component parts, possesses 

 many features common to all. In fishes, the posterior lobe has a complex 

 vascular structure of a glandular nature, which was called the "saccus 

 vasculosus" by Gottsche (12). L. Stieda (44) proved that the saccus 

 vasculosus communicates with the brain cavity, and Rabl-Riickhard (31) 

 named it an infundibular gland. Their researches have been confirmed 

 by Kupffer (21). The function of the saccus vasculosus is unknown, but 

 its secretion, if it is a secretory gland, apparently mixes with the fluid 

 contents of the ventricles of the brain. According to Kupffer, the 



