326 PROFESSOR FRANK J. COLE 



is sufficiently high to keep the sulphur at the surface. The rate of fall of the sulphur 

 particles was much more rapid with ox bile, but nevertheless with Myxine bile quite 

 a large quantity of the sulphur sank to the bottom of the tube. 



Since the above was written, Professor Mekk obtained a fresh supply of Myxine, 

 and I at once went to Cullercoats and collected the bile from about 100 specimens. 

 I find the best way to do this is to remove the two lobes of the liver separately, and 

 then detach the gall bladder from the gut. Severing the hepatic ducts and the bile 

 duct does not cause bile to escape from the cyst. The latter can then be washed free 

 of blood, and slit open inside a test-tube. All the bile is thus collected without any 

 admixture of blood. It varies greatly in colour from a pale yellow to a deep green. 

 The colour of the liver also varies considerably. 



The fresh bile is rather more gelatinous than that taken from animals kept for some 

 time in the laboratory tanks, and consequently the precipitate of nucleo-protein obtained 

 by acidifying the bile with acetic acid is much more pronounced. In the ether and 

 hydrochloric acid test a much greater proportion of pigment was extracted by the use 

 of dilute acid. 



Gmelin's ring test was more successful with the fresh bile. This is better carried 

 out by pouring a thin film of bile on to a clean porcelain tile, and then adding the acid. 

 The rings visible were a very faint yellow, red, violet passing into blue, and a very 

 faint green. The red and blue zones were the most predominant, and this suggests 

 that bilicyanin is in excess of the other pigments. 



4. Histology of the Gall Bladder. 



The gall bladder is lined by a single layer of epithelium. The cells are tall and 

 narrow, and may measure as much as 35 m by 3 m- The nucleus is at the base and the 

 chromatic material very concentrated, so that the nucleus stains a solid black with 

 iron hsematoxylin. The free border of the cells, looking like a string of beads, is 

 denser than the remainder, and readily strips off in imperfectly preserved material, or 

 the free surface may dispatch into the lumen of the gall bladder innumerable sessile 

 droplets. The cells are not in apparent contact, but are separated by a narrow non- 

 staining zone. In badly preserved material the cells shrink considerably, and are then 

 separated by intervals wide enough to be distinguishable under the low power of the 

 microscope. The cytoplasm of the cells is coarsely vacuolated. 



Immediately investing the lining epithelium is a complex fibrous coat. This is 

 essentially the vascular investment of the gall bladder, which, as shown by injections, 

 is richly vascular with a well- developed capillary system. Arteries and veins and their 

 connecting capillaries are readily distinguishable. Blood-vessels are very numerous 

 just under the epithelium, although in nearly all cases a few fibres intervene between 

 the vessels and the base of the epithelial cells. I have, however, here and there seen 

 fine vessels penetrate between the lining cells themselves. 



The fibrous coat falls readily into three layers — a central transverse one and an 



