58 Proceedings of Royal Society of Edinburgh. [sess. 
cells have undergone a mucoid change, and a band of clear cells is 
visible lining the duct. This appears to be a degeneration, since 
in other cases no such cells are to be seen. 
The blood filling the sinuses was often remarked to contain 
many large and very coarsely granular eosinopbilous cells. 
The general system of the organ recalls, therefore, that of a 
compound tubular gland with short secondary ducts opening into a 
main central one. It might also be considered, more correctly 
from a developmental point of view, as a blind tube having the 
same general structure as that of the intestine, and presenting a 
lumen bounded by walls of a constitution comparable to that of 
the intestine, though widely differing from that part of it in the 
near neighbourhood. 
The cells of the gland acini present no very peculiar feature ; 
they resemble in general character the cells of the kidney, and 
suggest an excretory function rather than a secretory. 
But what cannot fail to be noted in the structure of the organ 
is the richness of its blood-supply and the peculiar arrangement 
of that supply. There is a peripheral and a central arrangement 
of large blood-sinuses connected by a copious network of capillaries 
which bring the blood into intimate relation with the cells. 
And though this has been remarked, attention seems never to 
have been arrested by the position of the central sinuses, directly 
in relation with the epithelium of the lumen ; a condition which is 
surely uncommon. 
Chemical. 
Dr Noel Paton has been kind enough to make for me a chemical 
examination of the gland and its secretion, and has given me the 
following particulars : — The contained secretion of several rectal 
glands was preserved in absolute alcohol. The alcohol was evapor- 
ated off, and the residue extracted with water. A considerable 
amount of insoluble matter remained. The aqueous solution when 
treated with an alkaline solution of hypobromite of soda, gave a 
fine effervescence ; and on the addition of oxalic acid as it evapor- 
ated, yielded a crop of crystals, some with the characteristic shape 
of oxalate of urea, some long and acicular. The secretion from the 
gland undoubtedly contains a considerable amount of urea. 
