UMBILICARIA. 



175 



means of saving the crews from perishing by starvation. 

 The nutritive properties of the Umbilicarias depend on the 

 presence of a large amount of starchy matter. When boiled 

 they yield, like Cetraria Islandica, a firm, nutrient jelly, 

 which is however accompanied, as in that Lichen, by a bitter 

 principle possessed of purgative properties. This purgative 

 bitter has been the source of much danger to Arctic travel- 

 lers, who have been compelled to live for a time on " Tripe 

 de Roche." In the account of Franklin's first land expedi- 

 tion, as detailed in Simmonds's c Sir John Franklin and the 

 Arctic Regions/ occur the following passages illustrative of 

 this point : — " After feeding almost exclusively on several 

 species of Gyrophora (the Umbilicarias of this Work), a 

 Lichen known as c Tripe de Roche/ which scarcely allayed 

 the pangs of hunger, on the 10th they made a good meal 



by killing a musk-ox. . . . Mr. H was also reduced 



to a perfect shadow from the severe bowel complaint which 

 the Tripe de Roche never failed to give him. . . . Not being 

 able to find any Tripe de Roche, they drank an infusion of 

 the Labrador tea-plant {Ledum palustre), and ate a few 

 morsels of burnt leather for supper. This continued to be 

 a frequent occurrence." Linnaeus speaks of some Umbilica- 

 rias as superior in nutritive qualities to the Iceland Moss. 



