4 
DR. C. H. JONES ON THE STRUCTURE, DEVELOPMENT 
be extremely small, and cannot be actually discerned : this surely is not the condi- 
tion of a mere channel of passage, a mere outlet for an already elaborated fluid ; 
it surely betokens an active process of attraction, and probably chemical transforma- 
tion to be going on. 
The truth of this remark will be more apparent if we compare the condition of the 
epithelium of the ultimate or elaborating ducts with that of the large trunks ; in the 
former it has the characters we have just described ; in the latter it consists of a 
simple pavement of short columnar particles ; the one is in the condition of the 
ureter or any simple mucous surface, the other in that of the deeper parts of the 
gastric or renal tubule. 
I subjoin here the details of some examinations I have made in this class of animals, 
believing that I cannot in any better way convey an idea of the various appearances 
observed. In a Pike (Eso.r lucius), to whom I had given a dose of calomel, there 
was observed a peculiar condition of the ducts which seems worth noticing, although 
there was no reason to regard it as in any way produced by the drug. Many of the 
larger ducts were obstructed by a concrete deposit in their interior, which, viewed 
by direct light, was of a glistening white, and probably consisted of cholesterine or 
some bile-derived matter. At the obstructed parts the duct was considerably narrowed, 
while beyond it in the direction of ramification it was greatly dilated, sometimes to 
more than twice its natural magnitude ; the distended part forming a pouch of some- 
what globular form, into w’hich small absorbing ducts opened ; these must doubtless 
have existed, though they seemed in some cases to be more or less obliterated. The 
wall of the dilated part was greatly thickened, chiefly by an increase of its fibrous 
investment ; within this a homogeneous tunic was distinctly discernible, supporting 
a layer of epithelium, which was, 1 believe, of secreting function, and not a mere 
lining. The fluid contained in the dilated part was in some instances of a decided 
bilious colour, which probably depended on its having become concentrated by being 
retained in the canal longer than usual. The obstructions in the ducts had occasioned 
no noticeable change in the parenchyma ; it was tested for sugar by Trommer’s 
method, and gave distinct evidence that this was present. 
About the middle of February I examined a Roach (^Leuciscus rutilus^ veiy full of 
ova, the parenchyma of the liver was of a pale red tint and semitranslucent ; it con- 
sisted of nuclei, granular matter, and multitudes of delicate semitransparent vesicles 
packed closely together ; one or two tablets of cholesterine, and some biliary deposits 
were observed in it. 
One part of this liver formed a long thin tongue, and this viewed without being cut 
exhibited a beautiful capillary network perfectly injected with blood ; the vessels formed 
long narrow meshes ; and it was especially observable that, while there was scarcely 
any oil to be seen in other parts of the parenchyma, there were little groups of small 
oil-drops seated at intervals all along the sides of the vessels, as if it had just exuded 
from them. The ducts, when dissected out, were seen most perfectly ; all the elabo- 
rating ones were crowded with delicate pellucid vesicles, varying a good deal in size, 
