x THE GLYCO-PROTEIDS : MUCOIDS 541 



(b) The Mucoids 



Hammarsten has called a number of substances, which closely 

 resemble mucins in their composition and in their reactions, by the 

 name of mucoids. These mucoids differ from mucins either as regards 

 their physical properties or by not being precipitable with acids. 

 They are found partly in solution, as, for example, in blood-serum, 

 in the white of egg, or in ascitic fluid, and partly along with collagen, 

 etc., in the tissues. Their separation from the mucins is quite 

 arbitrary. The mucoids occurring in the vitreous humour, in tendons, 

 and in the umbilical cord are by some called mucoids, and by others 

 mucins, without their properties differing from one another in any 

 marked way. With the view of reserving the name " mucin " for the true 

 mucinous substances secreted by epithelia, Cohnheim calls all sub- 

 stances not derived from epithelium, but from connective tissues 

 " mucoids." The tissue-mucoids which resemble the mucins most will 

 be discussed in the first instance, and subsequently the soluble mucoids. 



1. Mucoid from Tendons and Bones 



Loebisch, 1 Chittenden and Gies, 2 and Cutter and Gies 3 have 

 isolated a substance from tendons which does not differ from the true 

 mucins in its properties. Its composition also resembles that of the 

 mucins, 4 the only exceptional feature being the high sulphur-content : 



C H N S 



48-26 6-49 11-51 2-31 31'43 



Levene 5 separated from this mucoid a substance closely resembling 

 chondro-sulphuric acid (see below). 



When boiled with acids, or with water under heightened 

 pressure, a high carbohydrate is liberated, which does not reduce, 

 which is slightly dextro-rotatory, and which, by more intense 

 action of acids, is converted into a reducing carbohydrate, which 



1 M. F. Loebisch, Zeitschr. f. physiol. Chem. 10. 40 (1885). 



2 R. H. Chittenden and W. Gies, Journ. of experiment. Med. 1. 186 (according to 

 Maltfs Jahresber. f. Tierchem. 26. 32) (1896). 



3 W. D. Cutter and W. J. Gies, Amer. Journ. of Physiol. 6. 155 (1901) ; compare 

 also A. N. Richards and W. J. Gies, ibid. 7. 93 (1902) ; G. W. Vandegrift and W. J. 

 Gies, ibid. 5. 287 (1901) ; S. Hunger and W. J. Gies, ibid. 6. 219 (1901). 



4 M. F. Loebisch, Zeitschr. f. physiol. Chem. 10. 40 (1885) ; R. H. Chittenden and 

 W. Gies, Journ. of experiment. Med. 1. 186 (according to Malys Jahresber. f. Tierchem. 

 26. 32) (1896) ; W. D. Cutter and W. X Gies, Amer. Journ. of Physiol. Q. 155 (1901); 

 compare also A. N. Richards and W. J. Gies, ibid. 7. 93 (1902) ; G. W. Vandegrift and 

 W. J. Gies, ibid. 5. 287 (1901) ; S. Bunger and W. J. Gies, ibid. 6. 219 (1901). 



5 P. A. Levene, Zeitschr. f. physiol. Chem. 31. 395 (1900). 



