262 Herring 



in the sagittal plane and mounted serially. In all cases a sufficiently large 

 portion of brain was included to display the immediate relationship which 

 exists between the brain and the pituitary body, a precaution which is of 

 importance. 



For the experimental part of the research, extracts of the various 

 structures revealed by the histological investigation were prepared, the 

 lobes of the pituitary being carefully separated from one another, finely 

 minced, and boiled in Ringer's fluid. The animals experimented upon 

 were cats, which were anaesthetised with a mixture of chloroform and 

 alcohol. After a tracheal tube had been introduced, anaesthesia was continued 

 by the administration of the same mixture through Brodie's apparatus, 

 with artificial respiration. Injections of the extracts were made through a 

 tube inserted in the external jugular vein. Blood-pressure was recorded by 

 means of a cannula in the carotid artery. The left kidney was placed in a 

 brass oncometer ; its movements were registered by a piston recorder. A 

 tube tied into the bladder drained away the urine, which was allowed to 

 fall drop by drop upon a recorder, an electrical signal marking on the paper 

 the moment of the falling of each drop. 



The Pituitary Body of Birds. 

 Histological Features. 



The type of bird's pituitary investigated has been that of the common 

 fowl, Gallus domesticus. The pituitary body of the adult fowl bears certain 

 general resemblances to that of mammals. It has two well-defined lobes — 

 an anterior or glandular, and a posterior or nervous. The epithelial cleft, 

 which is so prominent a feature of certain mammalian pituitaries, e.g. 

 those of the dog and cat, is absent from all the specimens of fowl's pituitary 

 that I have examined. The anterior lobe is a compact cylindrical body 

 with its long axis in an antero-posterior direction, deeply embedded in the 

 sella turcica. Large blood-vessels enter it at its lower posterior margin 

 and are a prominent feature in the initial dissection. The lobe itself is 

 very vascular, and contains large blood-channels running between solid 

 columns of cells. The cells are for the most part small and finely granular ; 

 larger cells containing granules which stain more deeply are occasionally 

 met with, but do not resemble the large deeply staining cells which are so 

 characteristic of the anterior lobe of the mammalian pituitary. The cells 

 have a close resemblance to those of the mammalian parathyroid. The lobe 

 is as a rule well defined, but in its upper part strands of cells frequently 

 pass towards the neck of the posterior lobe and are continuous with narrow 

 columns of cells which encircle this and spread over the adjacent brain- 

 tissue. Fig. 1 (of Plate) shows the general relationship of anterior to 

 posterior lobe and adjacent brain. It is taken from a median sagittal section 

 of a fowl's pituitary body. 



