x THE GLYCO-PROTEIDS : MUCOIDS 549 



Stahelin. 1 They found a mucoid, which imparted to the fluid an opales- 

 cent appearance and a peculiar viscosity. When pure the mucoid is 

 precipitated by means of acetic acid, but from ascitic fluid only 

 after the other albuminous substances have been removed and the salts 

 have been dialysed off, or after greatly diluting the ascitic fluid. 

 When the coagulable albumins are precipitated this mucoid is also 

 carried down according to Stabelin, but it is possible to bring it again 

 into solution. Umber diluted the ascitic fluid, precipitated with acetic 

 acid, and then purified the precipitate with alcohol and ether. The 

 mucoid is precipitated by the alkaloidal reagents, also by potassium 

 ferrocyanide, nitric acid, copper sulphate, ferric chloride, and lead 

 acetate. It gives all the colour-reactions of albumins. It is com- 

 pletely precipitated by half-saturated ammonium sulphate. As boiling 

 for a short time with acids gives rise to only very minute quantities 

 of a reducing substance, Umber and Stahelin have doubts as to 

 whether this mucoid is a mucin at all, but that it is really a mucin 

 has been shown by von Hoist 2 who, working under Hammarsten, has 

 made a very careful study of ascitic and synovial fluids. The ascitic 

 fluid obtained from a patient suffering from cancer ventriculi et 

 peritonei, was of a yellow colour, viscous, and distinctly alkaline to 

 litmus paper. The 'serosa-mucin' was precipitated by 1 per cent 

 acetic acid, then dissolved in just sufficient alkali, and this procedure 

 repeated thrice. The neutral solution obtained by dissolving the 

 precipitated mucin in alkali did not coagulate when it was boiled ; it 

 was precipitated by acetic and hydrochloric acid; was insoluble in 

 excess of acetic, but soluble in O'l - 0'5 per cent hydrochloric acid. 

 The neutral solution was not precipitated by such alkaloidal reagents 

 as sodium molybdate or potassium + mercury iodide ; it did not 

 directly reduce an alkaline copper solution, but did so after having 

 been boiled for half an hour in 2 per cent HC1. By pepsin + hydro- 

 chloric acid, a fraction amounting to 8 '1 per cent and containing 

 phosphorus could be removed without altering the properties of the 

 serosa-mucin, which now contained neither phosphorus nor iron, and 

 therefore could neither be a nucleo-proteid nor a nucleo-albumin. The 

 analysis of this serosa-mucin is included in the following table of von 

 Hoist's : 



1 Stahelin, Munchener med. Wochenschr. 1902, p. 1412. 

 2 Gustaf v. Hoist, Zeitsch. f. physiol. Chem. 43. 145 (1904). 



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