THE PIGMENT CELLS OF THE RETINA. 365 
The Pigment Cells of the Retina. 
By 
J.S. Boden and F. C. Sprawson, 
Students of Medicine, King’s College, London. 
in preparing a specimen of the retinal pigment cells from a 
sheep’s eye in the practical histology class at King’s College 
one of us (S.) noticed that these were not all hexagonal in 
shape, as is usually described, but that many had seven sides ; 
and on searching through the specimen, cells with varying 
numbers of sides were found. On showing this to Professor 
Halliburton he suggested that we should examine a large 
number of specimens from different animals, in order to ascer- 
tain if the same irregularities exist there. This we have done, 
and the present paper contains the results of the investigation. 
The descriptions and figures in the various text-books are 
taken from Max Schultze’s work on the subject.!’ In all, the 
cells are represented as being perfect hexagons, and the exist- 
ence of cells of other shapes is not mentioned. 
The method of preparation we employed was as follows :— 
The eye was removed from the body, and an incision having 
heen made through the sclerotic, it was placed in Miiller’s 
fluid for a few days. It was then transferred to very dilute 
Miller’s fluid for a day or two in order to macerate it a little, 
and the eyeball freely opened ; the black pigment layer can be 
stripped off fairly easily. Portions of this were mounted in 
glycerine or Farrant’s solution, and examined unstained. In 
some cases, especially when we examined that portion of the 
1 © Archiv f. mikr, Anat.,’ vol. il, and Stricker’s ‘ Handbook of Histology.’ 
