330 PEOFESSOR FRANK J. COLE 



to gut, had a total length in a 31 -cm. Hag of less than 4 mm. Of this the pancreas 

 extended over rather less than the half nearer the gut. 



The pancreatic alveoli, the structure of which varies very considerably, are situated 

 within the thickness of the connective-tissue coat of the bile duct, and in fact largely 

 within the serous wall of the gut. They may be found also even at the apex of the 

 papilla on which the bile duct discharges. Usually, however, there are more connective- 

 tissue fibres externally than internally to the alveoli, although I have always found a 

 well-marked zone of connective-tissue fibres between the pancreas and the epithelium 

 of the bile duct. 



The pancreas consists of a number of lobules or alveoli clustered round the distal 

 half of the bile duct. There is a vascular plexus round the bile duct, which also passes 

 freely between the lobules of the pancreas, the vessels, however, always remaining 

 outside the periphery of the lobules and never penetrating within them. The whole 

 gland is surrounded by a strong sheath of connective tissue, which further extends 

 freely among the alveoli, separating them from each other. There is no basement 

 membrane to the alveoli, but each is separated from the connective-tissue framework 

 by a very sparse layer of unstriped muscle. The lobules vary greatly in size, a fairly 

 large example having a diameter of 255 a. Most, but not all, of them have a cavity, 

 generally a relatively large cavity, which may have a diameter of even 195 m. One 

 specially large alveolus had a diameter of 345 /j- and a cavity of 240 m. 



The development of the lobular cavities varies considerably.* In those cases where 

 they are very large and frequent, I still do not find any connection between them and 

 the lumen of the bile duct. Sometimes the cavities of adjacent lobules approximate 

 and are only separated by a narrow partition. Nevertheless I have observed no fusion. 

 Again, spaces may appear sporadically in places outside the region of the pancreas, as, 

 for example, at the gall-bladder end of the bile duct, within the lining epithelium of the 

 duct itself. Instead of one large cavity a lobule may have five or more smaller ones, 

 which appear and disappear in an apparently capricious manner without discharging 

 anywhere. In nearly all cases the cavities are either partly or wholly surrounded by a 

 single layer of epithelium showing numerous mitoses, as in the epithelium of the bile 

 duct, and having in general a close resemblance to the latter epithelium. It is, in fact, 

 difficult to escape the conclusion that the pancreatic lobules are outgrowths from the 

 bile duct. 



Very rarely the connective tissue separating an alveolus from the lining of the bile 

 duct is interrupted, and the glandular mass fuses with the biliary epithelium, but only 

 in a few isolated cases have I observed any connection, or any appearance which might 

 be interpreted as. a connection, between the cavity of the gland and the lumen of the bile 

 duct. I have even seen the secretory section of a gland fuse with the epithelium of 



* Since tlie following paragraph was written 1 huve examined another series of sections, in which all the pancreatic 

 follicles were homogeneous and solid, and in which there conld be no ([uestion whatever of any dncts connecting them 

 with the bile duct. Fusions between certain of the follicles and the epithelium of the bile duct were observed, but 

 these fusions were wilhout the .slightest trace of a cavity. 



