CONCERNING THE SECRETION OF FERMENTS BY THE LIVER CELLS 45 t 



abundance of structureless material in large masses. The nuclei of the 

 outer zone cells are still swollen but less clouded, and contain some newly 

 formed karyosomes ; in the middle zones the nuclei are clearing up, but 

 are still very clouded in the inner zones. The small cells round the 

 portai tracts are resting; the capillaries are of moderate size. 



In this séries we hâve a striking proof that the first period of sécrétion 

 of ferments by the liver cells during digestion is due entirely to psychic 

 phenomena and corresponds with the «appetite juicc of the peptic glands; 

 it could not hâve been due to the digestion of any food, as every précaution 

 was taken to prevent such a mishap, and must, therefore, hâve been 

 entirely brought about by the excitement produced by either the smell or 

 sight of the food or by both; but in the bright light of day the vision of 

 white rats seems very imperfect, they never seize upon food without first 

 thoroughly smelling at it; and therefore I présume that with them appetite 

 sécrétion is excited solely through the olfactory sensé. 



Results obtained from the above five séries of experiments. 



i . The liver cells are called upon twice during the period of digestion 

 to produce ferments for the proper élaboration ofthe food in the intestines; 

 the amount of ferment produced is considérable and corresponds probably 

 to that described by Pawlow (') as reinforcing the action of the pancreatic 

 ferments. 



How it leaves the liver cells has not yet been ascertained, as beyond 

 its production from the nuclear chromatin as is usual with ail digetive fer- 

 ments nothing has been revealed by the spécimens under discussion, unless 

 the structureless material that stains as many zymogens do with eosine is 

 derived from the conversion ofthe prezymogen into zymogen. This, to my 

 mind, is highly probable because, as we hâve seen, it is abundant in the 

 fasting condition, diminishes in amount whilst the nuclei are parting with 

 prezymogen and may entirely disappear when they become fatigued, to 

 again make its appearance in the cells, in small quantity at first, but 

 increasing in amount as the cells and their nuclei recover. This is exactly 

 analogous to what occurs in the stomach glands of the newt as previously 



(') Pawlow : Ibid. 



