142 Herring 



Berkley (2) examined the nervous lobe of the pituitary of the dog, em- 

 ploying Golgi and other methods. He gives a description and diagram of 

 the posterior lobe of the dog's pituitary, and divides the organ into three 

 parts, all of which are microscopically dissimilar in appearance. " There is 

 first an outer lamina of slightly irregular ependymal cells, three or four 

 deep, arranged after the manner of the cuticular epithelium, separated into 

 divisions by thin processes extending from the fibres of the surrounding 

 capsule and terminating at a definite line where a separation from the 

 more internally lying elements occurs ; then follows a more internal zone 

 of varying depth, containing epithelial cells of a secretory type, which in 

 places along the posterior and inferior border of the lobe, as well as 

 occasionally in the more central regions, are arranged into distinct closed 

 acini lined with a low variety of cylindrical epithelial cell, and often hold 

 in their lumen collections of a colloid substance." Berkley in this passage 

 clearly describes as ependymal cells the long thin cells of the epithelial 

 investment, the nature of which has already been discussed. Berkley 

 further states : " The secretory region gradually merges into a central region 

 of small, rounded, and polygonal cells separated by extensive connective 

 tissue partitions, carrying blood-vessels, and scattered widely among these 

 cells are others of larger dimensions. Some of the latter are of spindle 

 form, others of pear or rounded shape, and still others of very irregular 

 form with their borders ill-defined ; all having a finely granular appearance, 

 with here and there larger granules scattered among them, that are tinged 

 by osmic acid a blackish colour. In the region of the neck of the infundi- 

 bulum the epithelial elements, except the outer ependymal row, become 

 segregated into groups of mainly oval and pear-shaped cells separated by 

 a fine stroma, with small nuclei here and there in it, and are now easily 

 recognised as nerve cells. A certain number of the spindle cells are very 

 long as well as broad, and probably correspond to those described by 

 Krause as spindle cells of uncertain function, but they are undoubtedly 

 nerve cells." Berkley gives a correct description of the structure of the 

 lobe, but with his statement that the epithelial cells become nerve cells, 

 I am quite unable to agree. He finds several varieties of neuroglia cells, 

 chiefly of the moss and spider type. No less than six varieties of nerve 

 cells, including large, medium, and small pyramidal cells, are described by 

 him as occurring in the posterior lobe of the pituitary. The axis cylinders 

 have a general tendency to pass upwards and forwards. Berkley con- 

 cludes that " the pituitary gland retains in the dog, as one of the highest 

 orders of vertebrates, its double role of secretory and nervous functions, 

 intact ; the former perhaps modified, the latter, the original special sense 

 organ, probably lying quiescent, not atrophied, and only changed in so far 

 as to admit of a slightly different arrangement of its constituent elements." 

 Berkley is quoted at length, because it is on the result of his work that 

 the belief in the presence of true nerve cells in the pituitary is mainly based. 

 Retzius finds no true nerve cells, and no medullated fibres, and inclines to 



