ECONOMIC USES OF LICHENS — LLANO 401 



extracted from Ramalina calicaHs (13) . The last-named acid was the 

 same as "Makao" obtained from the Manchurian drug "Shi-hoa." 



Lichens, with two exceptions, are nonpoisonous, though some acid 

 substances in others may be irritating wlien taken internally. The 

 poisonous exceptions are Evernia vuVpina and Getraria pinastri, both 

 a characteristic bright yellow. The former contains vulpinic acid in 

 the cortical cells, the crystals of which are yellow in the mass. The 

 latter species and Getraria juniperina Ach. produce pinastrinic acid in 

 the hyphae of the medulla, the crystals being orange or golden yel- 

 low. These lichens have been used in northern European countries to 

 poison wolves by mixing the lichens and powdered glass with the bait 

 ( 18) . Santesson isolated the crystalline acid and tested it on animals : 

 it produced respiratory difficulties, reducing the rate of breathing until 

 death ensued. Seshadri and coworkers extracted usnic and sekikaic 

 acids from Ramalina tayloriana Zahlbr., which when tested on fish 

 {Haplochilus pa7ichax) proved lethal. Z>-usnic acid in running water 

 (50 milligrams in hot absolute alcohol) proved toxic in 13 minutes; 

 sekikaic acid in 100 miligrams per liter was effective in 27 minutes or 

 in 6 minutes when the concentration was increased to 200 milli- 

 grams. It is further suggested by the authors that these lichen com- 

 ponents may be equally toxic to living plant tissue when physical 

 penetration is obtained by the lichen. 



More recently a report of the Wyoming Agricultural Experiment 

 Station, in a study of the presence of selenium in soil and various 

 plants, states that Parmelia moUiuscula Ach. contains this poison- 

 ous salt in sufficient quantities to affect sheep and cattle. It pro- 

 duces a lack of coordination of the hind limbs; in severe cases the 

 animals are unable to move either hind or fore legs. Other examples 

 of lichens containing such elements include beryllium in Parmelia 

 saxatilis Ach. and XantJioria parietina Th. Fr., chlorine in Evernia 

 furfuracea (13). 



Modern developments in lichenology. — Employment of lichens as 

 raw materials in pastries, confectionery, foods, and in the production 

 of alcohol depends largely on the properties of "lichen starch." The 

 presence of a certain number of phenols, acid-phenols and acid-phenol- 

 ethers, together with other substances in the extracts of some lichens, 

 forms the basis of their use in perfumery and cosmetics. The tincto- 

 rial properties of lichens are for the most part derivatives of orcinols, 

 as in species of Roccella. Besides possessing lichenin and isolichenin 

 and the sugar alcohols such as erythritol and manitol, lichens have 

 as their most characteristic components the lichen acids which seem 

 to be built on an altogether original pattern. In the past 60 years 

 more than 200 of these lichen-acid compounds have been isolated. 

 These compounds are, for the most part, known only from the class 

 Lichenes and were originally thought to be peculiar to them alone. 



