324 PROFESSOR FRANK J. COLE 



material down to 7 cm. in length. He describes cytozonal networks formed by the 

 bile channel splitting, surrounding little islands of several cells, and then joining up 

 again. I also find these. Braus confirms Retzius that the innumerable small blind 

 side capillaries given oS" from the central lumen of the tubule, which penetrate between 

 the liver cells, do not reach the periphery of the tubule. This is generally, but not 

 universally, true. He also states that, besides the nucleus, the body of the cells contains 

 large "nebenkerne" resembling corresponding structures in pancreatic tissue. He 

 believes these to be the remains of the achromatic spindle of recent mitoses, and thus 

 archoplasmic in character. M^hilst agreeing that the liver of Myxine is a tubular gland, 

 he describes certain deviations from the purely tubular structure which suggest the 

 origin of networks of bile capillaries. 



Holm states that the liver of Myxine is a typical tubular gland. He describes a 

 strong layer of unstriated muscle fibres round the larger blood-vessels which I have not 

 found, and asserts that the blind intercellular bile capillaries reach the periphery of the 

 tubule. He has injected the liver from the portal vein. 



3. Bio-chemistry of the Liver. 



I have not found it possible to overcome satisfactorily the practical ditiiculties in 

 the way of testing the secretion of the so-called " pancreas " of Myxine. The gland 

 itself is so very small that almost hundreds of dissections would be necessary, and its 

 situation is such that one could never guarantee any extract made from them would be 

 free from the secretion of the liver. In any case, however, this does not matter. As 

 far as my material is concerned, the " pancreas " can have no eff'ect on proteid digestion 

 in the animal. 



An eff"ective pancreas, therefore, being absent, the question is raised as to the 

 function of the liver. Two problems had to be solved : ( 1 ) Was the liver a true liver- 

 could it be compared with the liver of higher vertebrates? (2) Was it more than a liver 

 — i.e. was it also a digestive gland ? To the former point an answer in the affirmative 

 can be given. I had hoped to have included here an account of the digestion experi- 

 ments which have been carried out on the liver and gut of Myxine. These, however, 

 are not yet complete, and cannot now be completed until next year. The Hags 

 migrate into deeper water in the winter, and at the time of writing (September 23) 

 the females have already left, only one out of the 150 examined being a female. 



The chemical and physical properties of the contents of the gall bladder were 

 investigated in several freshly killed Myxine. I ought to add that these specimens had 

 been kept in the tanks at Cullercoats for some time, and it is well known that Myxine 

 do nob maintain their health in caj^tivity, nor will they feed. The following results 

 might lience have to be slightly modified if bile taken from animals fresh from the sea 

 were examined. Exactly similar experiments were carried out with a specimen of bile 

 taken from a freshly killed ox, the two series of observations being performed side 

 by side. 



