94 



Dr. Davy on the Bursa Fabricii. 



[Apr. 19, 



dition est sous presse et j'aurai I'honneur de la traiismettre a la Societe 

 Royale. Mais les nouvelles de ce qu'a trouve M. Schmidt ne peuvent 

 arriver qu'apres quelques mois. Dr. Ch. Ern. de Baer. 



St. Petersbourg, 1866. 



II. " On the Bursa Fabricii." By John Davy, M.D., F.R.S., &c. 



Received March 24, 1866. 



In this paper I have the honour to submit to the Society some observa- 

 tions which I have made on the Bursa Fabricii — an organ respecting the 

 function of which so little has yet been determined with any certainty, 

 some physiologists regarding it, after the manner of the author who first 

 described it, as a receptaculum seminis, others as the analogue of Cowper's 

 glands, others as that of the prostate ; and one as that of the urinary bladder 

 of fishes. 



For the sake of order and to save some repetition, before entering into 

 particulars it may not be amiss to state briefly that this peculiar organ, in 

 every instance it is met with, is found to lie low in the cavity of the pelvis, 

 behind the intestine, either directly in the median line, or a little on one 

 side of it ; that it is covered anteriorly by the reflected peritoneum ; is 

 composed mainly of two coats, one an outer muscular, the other an inner 

 mucous, the latter in the instances of most development abounding in 

 follicles ; that it communicates with the cloaca by an opening, in the female, 

 close to the entrance of the oviduct, in the male between and a little infe- 

 rior to that of each vas deferens, in both inferior to the termination of the 

 ureters* ; and that it has over its orifice, when most perfect, a slight val- 

 vular fold,''affording some, but not perfect, security against the entrance into 

 its cavity of fsecal matter whilst passing in the act of expulsion. 



What is remarkable in this organ, giving rise to much of the obscurity 

 adverted to, is the diff"erent aspects which it exhibits in the same animal 

 according to age, and the difl^erences as to form and proportional size and 

 degree of persistence which it presents in different species. 



The number of birds in which I have sought for the organ, and have ex- 

 amined it when found, has been considerable, at least thirty different species, 

 all of them, with the exception of the skylark, belonging to or frequenters 

 of the Lake district. 



I may further briefly premise that, when the microscope has been used, 

 the power employed has been that of ^th inch focal distance, and that, when 



* The ureters in those birds in which they are most easily traced, such as the common 

 fowl, turkey, goose, I have found not to terminate in the cloaca, but just above it, near, 

 or in the margin of the inner anal aperture (anus interne of M. Milne-Edwards), i. e. the 

 orifice of the rectum into the cloaca ; and, in consequence, the urinary excretion is voided 

 adhering to the inferior portion of the faecal mass which accumulates in the lower rectum — 

 which is unusually capacious and glandular ; accordingly, from such observations as I 

 have made, I cannot but entertain great doubt of the cloaca being the proper place for 

 the reception of the urine before its expulsion. 



