i7 



his pupils to an old castle in order to demonstrate ad oculos how the 

 green substance of Priestley, 1 when occurring on rocks, will develop 

 into lichens. These few citations will suffice to show that the science 

 of botany was in its infancy- 

 Better work was being done in the chemical study of lichens. 

 Here the investigations were limited to such lichens as had been 

 found useful in the arts and in medicine. Most of the results ob- 

 tained were published in the various chemical and pharmaceutical 

 journals of the time. Those specially interested will find the refer- 

 ences in various works on lichens. 



The investigations in regard to the medicinal uses of lichens were 

 not so extensive as in the previous period. During the wars of 1809— 

 1815 fevers of all sorts were prevalent in military hospitals. Quinine, 

 which was the popular remedy in all cases of fever, became very 

 scarce because of the enormous quantities consumed and because of 

 the commercial blockade of Europe. The Austrian government, 

 therefore, offered a prize of five hundred ducats for the discovery of 

 a cheap available substitute for quinine. Sanders, 2 who secured 

 this prize in part, proposed Parmelia -parietina as a substitute for 

 quinine. It was soon found that the medicinal properties of this 

 lichen were very unsatisfactory and the remedy was abandoned by 

 physicians. 



V. PERIOD. 



From Wallroth and Meyer (1825) to Schwendener (1868). 



This period marks the awakening of scientific lichenology as well 

 as of scientific botany in general. It also marks the discovery of the 

 " gonidia," which were destined to revolutionize the study and con- 

 ception of lichenology. Likewise the spore-characters were begin- 

 ning to be considered in the various systems of classification. We 

 may well be astounded when we recollect that from Dioscorides to 

 Wallroth, a period of two thousand years or more, the advance made 

 in the exact knowledge of the anatomy of lichens was practically 

 zero. The mere collection and arbitrary arrangement of plants do 

 not give us any insight into their true nature. 



1 Wiegmann, A. F. Erzeugung mehrerev Gewachse aus der Priestley'scben 

 griinen Materie. Flora, 4: 8-15. 1821. 



2 Sanders, G. C. H. Die Wandflechte (Parmelia parietina) ein Arzneimittel. 

 Sonderhausen. 1S15. 



