38 CHARLES F. W. McCLURE 



the reactions of the tissues toward these dyes, however, in the two 

 sets of experiments. When the portal of entry is restricted to the 

 skin, dye is stored by the epithelium of the tubules in the kidney, 

 before dye granules make their appearance in the stellate cells of 

 the liver capillaries. On the other hand, when the portal of entry 

 is restricted to the intestinal mucosa, the stellate cells of the liver 

 capillaries store the dye before the epithelium of the kidney. 

 Irrespective of its portal of entry, however, the mononuclear 

 leucocytes of the body have often been observed to store the dye 

 before any visible signs of dye can be found in the liver or kidneys. 



When the portal of entry of the dye is restricted to the integu- 

 ment, the dye is taken up from the intercellular tissue spaces by 

 the lymphatics, and conveyed with the transudated lymph to the 

 venous circulation. The lymph and dye which enter the veins 

 through the posterior lymph-hearts in the adult mixes with blood 

 which is immediately and directly conveyed to the kidneys by the 

 renal-portal (Jacobson's) veins. From the kidneys this blood is 

 then conveyed by the postcava to the heart from which it is dis- 

 tributed to the pulmonary and cutaneous circulations. When 

 lymph enters the venous circulation by way of the anterior lymph- 

 hearts, it mixes with blood which, for the most part, must pass 

 through the pulmonary and cutaneous circuits, before it can 

 reach the liver and kidneys by the hepatic artery, portal vein, 

 renal arteries or renal-portal veins. The circumstance that dye 

 is first stored in the adult by the epithelium of the renal tubules, 

 in cases where its portal of entry is restricted to the skin of the 

 posterior regions, is probably due to the fact that the kidney is 

 the first organ to be acted upon by the dye. In the case of young 

 larvae in which the posterior lymph-hearts are wanting and the 

 mesonephroi do not function, the pronephroi are without question 

 reached by the dye solution before the stellate cells of the liver 

 capillaries. The blood supply to the mesonephroi through the 

 renal-portal veins in later larval stages is also more extensive and 

 direct than that to the liver which may account for the earlier 

 reaction of the mesonephroi in such cases. 



If the passage of colloidal acid dye solutions through the intes- 

 tinal mucosa is a process entirely analogous to that of certain 



