THE LIVER. 421 



Of the forces which are at work in bringing about these various 

 changes in the liver we know very little, but to judge from recent 

 observations it appears certain that various tissue ferments are here 

 active. 



The reaction of the living liver-tissue is alkaline. After death, 

 however, it becomes acid, and there is reason to believe that, as in 

 the case of the muscle-tissue, this acid reaction is essentially refer- 

 able to the formation of lactic acid. At the same time the tissue 

 becomes opaque, owing to a coagulation of the liver albumins. 



A general idea of the chemical composition of the liver may be 

 formed from the following analyses, which are taken from v. Bibra : 



Man. Ox. 



Water 761.7 713.9 



Solids 238.3 286.1 



Soluble albumins 24.0 23.5 



Albuminoids 33.7 62.5 



Fats 25.0 32.8 



Extractives 60.7 49.1 



Insoluble portion 94.4 112.9 



The mineral salts, according to v. Bibra, constitute about 1 per 

 cent, of the fresh tissue, and are essentially represented by the phos- 

 phates of potassium and sodium and a fairly large amount of iron. 

 Traces of manganese, copper, and lead are also found. 



The Albumins. The albumins of the liver-tissue have been 

 notably studied by Halliburton and Plosz. The gland was freed 

 from blood and bile by transfusion with ice-water containing 0.75 

 per cent, of common salt. The tissue was then cut into small pieces 

 with cooled knives, frozen and placed under pressure. On thawing, 

 an alkaline fluid could thus be obtained, which represents the liver- 

 plasma. In this fluid a globulin exists which coagulates at 45 C., 

 and is regarded by Halliburton as being possibly identical with one 

 of his cell-globulins. It can be digested by gastric juice. In addi- 

 tion a nucleoproteid was found, which coagulated at 70 C., and 

 which yielded an insoluble residue of nuclein on digestion. From 

 the cells proper they extracted a globulin with a 10 per cent, solution 

 of sodium chloride, which coagulated at 75 C., and which may also 

 be identical with one of Halliburton 's cell-globulins ; further, an 

 albumin (coagulation -point 70-73 C.) and an alkaline albuminate. 

 In addition, a glucoproteid has also been demonstrated, which yields 

 a reducing substance on boiling with dilute mineral acids, and 

 which is probably of a mucinous character and derived from the 

 connective tissue of the organ. According to Wohlgemuth, the 

 nucleoproteid of the liver contains 2.98 per cent, of phosphorus, 

 and a pentose, which he identified as ^-xylose. 



The nuclei finally contain nucleoproteid, and it is of special 

 interest to note that at least two of these contain iron. The one is 

 apparently identical with, or at least closely related to, the hcemato- 

 gen of birds 7 eggs, while in the other, which Zalesky terms hepatin, 

 the iron is even more firmly combined. The occurrence of these 



