4IO ECONOMIC AND TECHNICAL 



C. Lichens as Poisons 



Though the acid substances of lichens are most of them extremely- 

 irritating when taken internally, very few lichens are poisonous. Keegan' 

 writing on this subject considers this quality of comparative innocuousness 

 as a distinctive difference between fungi and lichens and he decides that 

 it proves the latter to be higher organisms from a physiological point of 

 view: "the colouring matters being true products of deassimilation, whereas 

 those of fungi are decomposition or degradation waste products of the 

 albuminoids akin to alkaloids." 



The two outstanding exceptions to this general statement are the two 

 Alpine species Letharia yulpina and Cetraria pinastri. The former contains 

 vulpinic acid in the cortical cells, the crystals of which are lemon-yellow in 

 the mass. Cetraria pinastri produces pinastrinic acid in the hyphae of the 

 medulla and the crystals are a beautiful orange or golden yellow. 



These lichens, more especially Letharia vulpina, have been used by 

 Northern peoples to poison wolves. Dead carcasses are stuffed with 

 a mixture of lichen and powdered glass and exposed in the haunts of 

 wolves in time of frost. Henneguy^, who insists on the non-poisonous 

 character of all lichens, asserts that the broken glass is the fatal ingredient 

 in the mixture, but Kobert^ who has proved the poisonous nature of vul- 

 pinic acid, says that the wounds caused by the glass render the internal 

 organs extremely sensitive to the action of the lichen. 



Kobert, Neubert* and others have recorded the results of experiments 

 on living animals with these poisons. They find that Letharia vulpina either 

 powdered or in solution has an exciting effect on the mucous membrane. 

 Elementary organisms treated with a solution of the lichen succumbed 

 more quickly than in a solution of the acid as a salt. Kobert concluded 

 that vulpinic acid is a poison of protoplasm. 



He further tested the effect of the poison on both cold- and warm-blooded 

 animals. Administered as a sodium salt, 4 mg. proved fatal to frogs. The 

 effect on warm-blooded animals was similar. A sodium salt, whether 

 swallowed or administered as subcutaneous or intravenous injections, was 

 poisonous. Cats were the most sensitive — hedgehogs the least— of all the 

 animals that were subjected to the experiments. Volkard's' synthetic pre- 

 paration of vulpinic acid gave the same results as the solution, directly 

 extracted from the lichens. 



1 Keegan 1905. 2 Henneguy 1883. ■= Kobert 1895. * Neubert 1893. 



* See p. 228 



