ECONOMIC USES OF LICHENS — LLANO 397 



Analyses have shown that they contain a variety of carbohydrates of 

 which polysaccharides are the most common, giving rise on hydration 

 to several sugars, some cellulose, chitosan, glucosamine, and inulin. 

 Of these the only compounds directly available in intermediate meta- 

 bolism are the simple monosaccharides, i. e., six-carbon sugars. Poly- 

 saccharides apparently need to be split into "physiological" sugars 

 before they become available to the body. Uhlanders and Tollens 

 (13) noted a difference in the occurrence of characteristic carbo- 

 hydrates in various lichens examined, though they all contained some 

 lichenin. Thinking that the substances in Cetraria islandica and C. 

 nivalis were similar, Poulsson (13) made a bread from these two 

 species to determine their use in diabetes mellitus. Though 46 to 49 

 percent of the carbohydrates of the former species was digested, the 

 latter species caused such intestinal disturbances that the experiment 

 had to be discontinued. 



From a correspondent the author has received interesting informa- 

 tion on the personal use of Cladonia rangiferina to combat anemia 

 and a general run-down condition. The individual attempted self- 

 medication with this lichen on the advice of a Norwegian professor 

 who recommended the treatment as an old-time remedy. He reported 

 a gain of 7 pounds in 1 week and return of normal skin color and 

 physical strength, and states that he has become extremely active. It 

 is not known how the lichen was prepared, but the original supply was 

 obtained from Norway notwithstanding the fact that it is a common 

 plant of North America. 



Brown (13) failed to induce glycogen formation in rabbits by feed- 

 ing them lichenin obtained from C. islandica. Ordinarily neither 

 hydrochloric acid (0.3 to 0.5 percent) nor amylytic enzymes have any 

 noticeable effect on lichenin, while iso-lichenin is, at most, converted 

 into a dextrinlike form without producing sugar ; the action of bac- 

 teria yields acetic, propionic, butyric, and lactic acids. 



More recently Wallerstein (13) fed mice white bread, later replac- 

 ing it with lichenin, and showed the latter to be 53 to 64 percent 

 utilized. Similarly Shimizer (13), in determining the influence of 

 some polysaccharides on the protein balance of a dog, found that they 

 were digestible and available foodstuffs in the alimentary canal. 

 Later he digested polysaccharides in vitro, using extracts of macerated 

 intestine and pancreas in an 0.8-percent NaCl solution, but found no 

 monosaccharides. He took this as evidence that there are no enzymes 

 in the digestive system of mammals capable of splitting inulin, 

 lichenin, or hemicelluloses. On determining the action of fecal mate- 

 rial and fermentative bacteria on these substances, Shimizer and Toni- 

 hide (13) concluded that they are split into sugars by the bacteria 

 in the digestive tract of mammals and can then be absorbed. 



