A CONTRIBUTION TO THE COMPARATIVE PHYSIOLOGY OF THE 

 PITUITARY BODY. By P. T. Herring. (From the Physiology 

 Department, University of Edinburgh.) (With one Plate and eight 

 figures in the text.) 



(Received for publication 21st July 1908.) 



The researches of Oliver and Schafer (7), Howell (4), and others have 

 demonstrated the existence in the mammalian pituitary body of active prin- 

 ciples which have a specific effect upon the heart and blood-vessels when 

 injected intravenously. Howell, moreover, pointed out that it is the 

 posterior lobe alone which possesses this property. Magnus and Schafer 

 (5), and more recently Schafer and Herring (10), showed that extracts of 

 the posterior lobe have the additional characteristic of producing kidney 

 dilatation and diuresis when injected. Their observations were confined to 

 the pituitary body of certain mammals and of the cod, which was found to 

 have a similar action. Osborne and Vincent (8) had previously shown 

 that extracts of the pituitary body of the cod produce effects upon the heart 

 and blood-vessels similar to those of extracts of the mammalian posterior 

 lobe. The question as to the origin of the active principles found in the 

 posterior lobe of the mammalian pituitary has been discussed in a previous 

 paper (3), and the author has given reasons which appear to him to support 

 the view that they are derived from the cells of the pars intermedia, which 

 in the mammalian pituitary form so close an investment over the nervous 

 tissue of the posterior lobe. It was thought that an examination of the 

 structure of the pituitary body of other classes of vertebrates, combined 

 with an experimental investigation of the action of extracts of the different 

 parts of each, might furnish some interesting facts bearing upon the phj^si- 

 ology of the pituitary body, and at the same time throw light upon the 

 mode of origin of the active material. 



The difficulty of obtaining sufficient material for extracts has so far 

 prevented an investigation of the pituitary bodies of reptiles, amphibians, 

 and the lower orders of fishes. The present paper is confined to a descrip- 

 tion of the general structure of the pituitary body, and the physiological 

 action of its extracts, in birds and in bony and cartilaginous fishes. 



Methods. 

 The pituitary bodies of the types examined were fixed for histological 

 examination in Flemming's ffuid. Sections were cut by the paraffin method 



