NOTES ON CETRARIA ISLANDICA (ICELAND 



MOSS).* 



BY ERNEST W. BROWN. 



FROM early times lichens have been utilized as articles of diet 

 for man and domestic animals, f First among them in im- 

 portance as a food-stuff is " Iceland moss " (Cetraria islandica), 

 which seems to have recommended itself because of its large 

 content of carbohydrate matter, the so-called lichen-starch. 

 In its natural form this lichen contains bitter constituents, 

 and these must be removed by treatment with water or weak 

 alkalies before the material can be made into bread, as has 

 been the custom in some northern countries. Rabbits almost 

 invariably refuse to eat the lichen unless it has been rendered 

 more palatable as described. 



With reference to the real dietetic value of Cetraria islandica, 

 the following analysis of the commercial material will afford 

 some data | : 



ANALYSIS OP CETRARIA ISLANDICA (DRIED AT 106 C.). 



Total nitrogen 0.56 per cent 



Extractive nitrogen 0.14 " 



"Protein "nitrogen 0.32 " 



Ether extract 1.2 " 



Crude fiber 5.8 



Ash 2.2 



Material soluble in 85 per cent alcohol . . 16.1 " 

 Soluble carbohydrates (as dextrose) . . . 43.3 " 

 After successive treatment with gastric juice and amylolytically and pro- 

 teolytically active pancreatic juice at 38 C. only 32 per cent of the material 

 used was dissolved. The residue resisting digestion contained practically all 

 the original nitrogen (0.55 per cent) of the lichen. 



Reprinted from the American Journal of Physiology, vol. i. 



t Cf. Albert Schneider, A Text-book of General Lichenology, 1897. 



t The methods of analysis employed were essentially the same as described 

 by L. B. Mendel, Amer. Journ. Physiol., 1898, i, p. 226. 



This consisted of free fatty acids (0.4 per cent) and saponifiable fat (0.62 

 per cent). 



