x THE GLYCO-PROTEIDS : MUCOIDS 547 



acid in thirty minutes, according to Young ; amongst the dissociation- 

 products is found indol. 



The analyses of Morner and Young yield the same figures as 

 obtained with other mucins. 



The notochord, which otherwise resembles the umbilical cord, does 

 not contain any mucoid, according to Kossel 1 (compare with p. 578). 



4. Ovi-mucoid. 



Neumeister 2 and Salkowski 3 had observed that white of egg 

 contains, besides the well-known albumin and globulin, another 

 substance which has properties of an albumose. This body Neumeister 

 called pseudo-peptone. Morner 4 recognised that the new substance 

 was a glyco-proteid, and hence called it ovi-mucoid. It occurs in 

 large quantities in white of egg, forming about one-eighth of the 

 organic constituents, or 1'5 per cent of the solution. The ovi-mucoid 

 .resembles the other mucoids in not being coagulated by heat, but it 

 is also not precipitated by acids such as acetic, hydrochloric, or 

 nitric acids, or by metallic salts or most of the alkaloidal reagents. 

 It is, however, precipitated by tannic acid, phosphomolybdic acid, 

 lead acetate + ammonia, and by alcohol. The best method of pre- 

 paring it consists in first removing the albumin and the globulins of 

 the eggwhite, by heating the latter after slight acidification, and then 

 precipitating the mucoid, in the filtrate, with alcohol. When dried, 

 it forms brittle, transparent lamella ; a concentrated solution is 

 adhesive like gum; a dilute solution foams strongly, but cannot be 

 pulled out into threads. In cold water it simply swells up, without 

 passing into solution, but on heating it dissolves, and does not 

 separate out on cooling. According to Morner, it contains 



12 '65 per cent of N, and 2 "2 per cent of S. 



The greater part of the sulphur may be split off by boiling with 

 alkalies, but Zanetti 5 finds that boiling with hydrochloric acid liber- 

 ates sulphuric acid, and this must, therefore, have originally been in 

 the form of ethereal sulphuric acid. In addition to the lead-sulphide 

 reaction, ovi-mucoid also gives the reaction of Millon, and the biuret 

 and xanthoproteic tests, while, according to Morner, it does not give 

 the reactions of Liebermann or Adamkiewicz, and therefore it does 



1 A. Kossel, Zeitschr. f. physiol. Chem. 15. 331 (1891). 



2 R. Neumeister, Zeitschr. f. Biolog. 27. 309 (1890). 



3 E. Salkowski, Zentralbl. f. d. med. Wiss. 1893, No. 31. 



4 C. T. Morner, Zeitschr. f. physiol. Chem. 18. 525 (1893). 



5 C. U. Zanetti, Ann. di Chim. e Farmac. 12. According to Maly's Jahresber.f. 

 Tierchem. 27- 31 (1897). 



