THE PITUITARY BODY 145 



well kno^nl. Before the beginning of puberty, the eels, male and 

 female alike, have a green and yellow coloration, dark brownish 

 green on the back, and bright yellow o*n the belly. These colours 

 now change ; the green takes on a shade of purple and the yellow 

 of the belly fades away and becomes a pearly white. There is also 

 noted an apparent increase in the size of the eyes, they protrude 

 more, in fact there is a condition allied to exophthalmos. Associated 

 with these external appearances we have noted a great increase in 

 size of the jDosterior lobe and also a gradual replacement of the 

 peripheral cells of the alveoli by yellow colloid secretion which also 

 appears in the surrounding capillaries. It seems, therefore, that the 

 theory that these colour changes are connected with the increased 

 size of the lobe and the secretory activity receives some support 

 from the analogy of the pigmentary reponse in amphibia as des- 

 cribed by Hogben. Before referring in detail to other changes in 

 the pituitary gland at the time of approaching migration it will 

 be necessary to say something about the microscopic appearances 

 of the anterior lobe. 



Compared to the posterior lobe, the anterior is very vascular. 

 It consists of groups and columns of epithelial cells with dilated 

 sinusoids. The cells are either cliromophil or chromophobe. The 

 chromophil are either acidophil or basophil. The acidophil cells 

 are granular and stain pink with eosin, while the basophil cells 

 stain with haematoxylin and are larger than the eosin-staining, 

 though their granules are smaller. The sinusoids vary much in size, 

 and in that part of the anterior lobe, which faces the opening of the 

 infmidibulum, there is a wide depression occupied by what appears 

 to be a stringy secretion, and deep pits dip into the epithelial portion 

 of the gland. Anterior to the infimdibulum the stalk of the pituitary 

 descends from the margin of the lobus infundibuH. In addition 

 to the secretion above mentioned it is important to notice the 

 small globular refractile bodies described in the mammalian pituitary 

 by Poppa and Fielding. These globules are seen to be present in 

 considerable numbers in the hilum facing the infundibulum and 

 I have counted twenty globules of various sizes in two consecutive 

 serial sections and in a neighbouring section, two vessels have been 

 cut in a longitudinal direction containing numerous globules which 

 give the apjDearance of a string of beads and others are seen lying 

 free. 



These vessels communicate with the capillaries of the pia mater 

 clothing, the ventral margin of the lobus infundibuH and from 

 these vessels ascending branches supply the tissues of the stalk. 

 The above is the appearance of a section of the gland in the autumn, 



K 



