526 Drs. P. T. Herring and S. Simpson. [May 1, 



the "portal unit." Extravasation does not take place from the bile 

 capillaries, but only from the duct as it communicates with the capillaries, as 

 well as from the larger bile ducts. Mall finds that the lymphatics of the 

 liver do not drain all portions of the liver, but only those parts formed by 

 the centres of the " portal units." He states that there are no lymphatics in 

 the centres of the lobules, nor at the nodal points. 



In a paper (11) published last summer we gave reasons for concluding that 

 there are no lymphatics in the liver lobules at all ; they are confined to the 

 portal spaces, i.e., to the centres of the " portal units " of Mall. 



The question of bile absorption resolves itself into that of the mode of 

 formation of lymph in the liver. If there are no lymphatics in the lobules 

 of the liver, and the production of liver lymph is to be regarded as purely 

 mechanical, its source must be confined to the portal spaces. In this case 

 the interlobular veins must be extraordinarily permeable to allow the 

 passage outwards into the lymphatics of so large an amount of concentrated 

 lymph. On the other hand, if the liver cells take part in its formation, the 

 lymph must be secreted at the periphery of the lobules, and if all the cells 

 in the lobule participate there must be something of the nature of a com- 

 munication from cell to cell throughout the lobule. Given such a mechanism, 

 the secretion of lymph may be regarded as a vital act on the part of the 

 liver cells. We hoped that we might by our experiments throw some light 

 upon this question. 



Methods Employed. 



After determining in the manner already indicated the maximum pressure 

 of bile secretion in an animal we allowed the obstructed bile to escape from 

 the bile passages. A piece of rubber tubing leading from a reservoir 

 containing carmine gelatine was then slipped over the cannula in the 

 common bile duct, and the bile passages were injected with carmine gelatine 

 at pressures varying in different animals. We made use of an apparatus by 

 means of which we could inject at pressures measured in terms of the height 

 in millimetres of a vertical column of water. The difference in pressure 

 between similar heights of a column of bile and a column of water being 

 practically negligible, the pressures may be regarded as sufficiently alike. 

 In most cases we employed a pressure of injection not exceeding the 

 maximum of bile pressure previously recorded in the animal. In some cases 

 the injection was continued and the bile duct ligatured before the animal was 

 killed. In others the injection was made post mortem, the animal being 

 killed by an overdose of chloroform, or by opening the inferior vena cava 

 above the diaphragm so as to avoid a rise of blood pressure in the liver. 

 Sometimes we used an injection pressure higher than the maximum bile 



