242 GASTRIC JUICE. [BOOK n, 



35 to 40 C., the fibrin will speedily, in some cases in a few 

 minutes, be dissolved. The shreds first swell up and become 

 transparent, then gradually dissolve, being especially liable to fall 

 to pieces into flakes when the vessel containing them is shaken, 

 and finally disappear with the exception of some granular debris, 

 the amount of which, though generally small, varies according to 

 circumstances. 



If small morsels of coagulated albumin, such as white of egg, be 

 treated in the same way, the same solution is observed. The 

 pieces become transparent at their surfaces ; this is especially seen 

 at the edges, which gradually become rounded down; and solution 

 steadily progresses from the outside of the pieces inwards. 



If any other form of coagulated albumin (e.g. precipitated 

 acid- or alkali-albumin, suspended in water and boiled) be treated 

 in the same way, a similar solution takes place. The readiness 

 with which the solution is effected, will depend, ceteris paribus, 

 on the smallness of the pieces, or rather on the amount of surface 

 as compared with bulk, which is presented to the action of the juice. 



Gastric juice then readily dissolves coagulated proteids, which 

 otherwise are insoluble, or soluble only, and that with difficulty, in 

 very strong acids. 



Nature of the change as shewn by the products of the action. 



If raw white of egg, largely diluted with water and strained, be 

 treated with a sufficient quantity of dilute hydrochloric acid, the 

 opalescence or turbidity which appeared in the white of egg on 

 dilution, and which is due to the precipitation of various forms of 

 globulin, disappears, and a clear mixture results. If a portion of 

 the mixture be at once boiled, a large deposit of coagulated albu- 

 min occurs. If, however, the mixture be exposed to 50 or 55 C. 

 for some time, the amount of coagulation which is produced by 

 boiling a specimen becomes less, and, finally, boiling produces no 

 coagulation whatever. By neutralisation, however, the whole of 

 the albumin (with such restrictions as the presence of certain 

 neutral salts may cause) may be obtained in the form of acid- 

 albumin or syntonin, the filtrate after neutralisation containing no 

 proteids at all (or a very small quantity). Thus the whole of the 

 albumin present in the white of egg is converted, by the simple 

 action of dilute hydrochloric acid, into acid-albumin or syntonin. 



If the same white of egg be treated with gastric juice instead of 

 simple dilute hydrochloric acid, the events for some time seem the 

 same. Thus after a while boiling causes no coagulation, while 

 neutralisation gives a considerable precipitate of a proteid body, 

 which, being insoluble in water and in dilute sodium chloride 

 solutions, and soluble in dilute alkali arid acids, at least closely 

 resembles syntonin. But it is found that only a portion of the 

 proteids originally present in the white of egg can thus be regained 

 by precipitation. A great deal is still retained in the filtrate after 



