870 



from which to generalize. I have no doubt that a great proportion 

 of the obscurity overhanging this subject, depends on the circumstance 

 that many of the chemists who have devoted attention to the colour- 

 educts and products of the lichens were not themselves botanists, and 

 have therefore probably, in some cases, at least, analyzed species 

 under erroneous names, and also because their investigations have 

 comprehended a much too limited number of species. 



" 2. Their taxonomy, or classijication. This, however, is but a 

 secondary, and comparatively unimportant, departna^nt, and can only 

 be put upon a proper basis when the anatomy and physiology of the 

 lichens have been fully investigated, and their laws firmly established. 



" 3. Their geographical distribution , a subject of no little interest 

 in studying terrestrial nature on the large scale. 



" 4. Their utility. 



" a. In medicine. On examining the literature of this branch of 

 lichenology, I found that the lichens were, at one time in the history 

 of medicine, regarded as a panacea, every kind and degree of thera- 

 peutic action having been, by ' the profession,' as well as the ' profa- 

 num vulgus,' attributed to them. Being very sceptical on the matter, 

 I was naturally anxious to test these therapeutic actions, by experi- 

 menting, with the old officinal ? species and their active principles, on 

 man and the lower animals ; but such experiments I have been 

 obliged, for the present, to delay. 



" b. In the arts, and especially in dyeing, including the collection of 

 a series of the commercial dye-lichens, i. e., those used by the manu- 

 facturers of London, &c., in the making of orchil, cudbear, litmus, and 

 other lichen-dyes. While investigating the dyeing properties of the 

 lichens, I made experiments, with a view to test their colorific power, 

 on as many species as I could obtain in sufficient quantity to render 

 it at all useful to operate on, that number, however, being very limited 

 (between forty and fifty). But these experiments were speedily 

 brought to a stand, on account of a paucity of material to work 

 upon ; and one of my objects in placing the present remarks before 

 the Society, is to request such members and their friends as have a 

 superabundance of specimens of lichens, or are favourably situated 

 for collecting them, and may be willing to sacrifice a few to such a 

 purpose, to co-operate in furthering this branch of lichenology, by 

 contributing a few of their spare duplicates. They need neither be 

 rare nor fine specimens ; fragments, of every size and appearance, 

 are equally acceptable ; indeed, I may emphatically say, in the usual 

 words of the scrap-book title-page, ' Scraps thankfully received.' 



