A manual of physiology; with practical exercises

by George Neil Stewart

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899 ... mouth, is due to a similar action of the hepatic cells. (2) If blood from a dog killed during digestion is perfused through an excised liver, some urea is formed, which cannot be simply washed out of the liver-cells, because when the blood of a fasting animal is treated in the same way there is no apparent formation of urea (v. Schroeder). This suggests that during digestion certain substances which the liver is capable of changing into urea enter the blood in such amount that a surplus remains for a time unaltered. These substances may come directly from the intestine; or they may be products of general metabolism, which is increased while digestion is going on; or they may arise both in the intestine and in the tissues. Leucin--which, as we have seen, is constantly, or, at least, very frequently, present in the intestine during digestion--can certainly be changed into urea in the body, and there is every reason to believe that the change takes place in the liver. (3) Uric acid--which in birds is the chief end-product of proteid metabolism, as urea is in mammals--is formed in the goose largely, and almost exclusively, in the liver. This has been most clearly shown by the experiments of Minkowski, who took advantage of the communication between the portal and renal-portal veins (p. 328) to extirpate the liver in geese. When the portal is ligatured the blood from the alimentary canal can still pass by the roundabout road of the kidney to the inferior cava, and the animals survive for six to twenty hours. While in the normal goose 50 to 60 per cent, of the total nitrogen is eliminated as uric acid in the urine, and only 9 to 18 per cent, as ammonia, in the operated goose uric acid represents only 3 to 6 per cent, of the total nitrogen, and ammonia 50 to 60 p...

330 pages, Paperback

Published May 21, 2012

About the author

1860-