40 • DR. LAUDEE LTITDSAT ON CHEMICAL REACTIOIS^ 



years ago *. I confess that, had the propounders of the ^' tests in 

 question been authorities of less celebrity, I should not have con- 

 sidered it necessary to give myself the trouble of verifying or 

 correcting their observations, or of revising my own former inquiry 

 on a closely allied subject. But Nylander and Leighton are men 

 of such experience and reputation, while their assertions are so 

 confident, that I have deemed it desirable to attempt the recon- 

 ciliation of the discrepancy between their observations and my 

 own, on the one hand by repeating and extending their experi- 

 ments, and on the other by revising my own former researches. 

 My own experimental inquiry relates to the 



Reaction of (a.) hypochlorite of calcium, 



(b.) hypochlorite of sodium, 

 (c.) aqua potassse, 

 (J.) aqua ammoniae, 

 (e.) iodine solution. 



I. On the thallus, — direct application. 



(a.) Cortical, K-^^^^^ 

 (b.) Medullary J 



II. On aj^othecia^-^irecf application. 



(a,) Disk and exciple. 

 (6.) Hy menial licheninef- 

 (c.) Asci and sporidia. 



III. On aqueous or alcoholic decoctions of 

 thallus, with or without apothecia, the 

 plant being reduced to powder or frag- 

 ments. 



I confined myself as far as possible to the specimens contained in 

 published fasciculi ;f, because they are accessible to all lichenolo- 

 gists, and bear names whose synonyms can be readily ascertained. 

 In special cases, of common species, I experimented on the very 

 considerable contents of my own herbarium. Thus of the cosmo- 

 polite Cladonia rangiferina [including its 8 varieties or forms, 

 Bylvatica^ Hfim. ; alpestris, Ach. ; gigantea, Ach. ; pumila, Ach. ; 



* *' Experimental Researches on the Tinctorial Properties of Lichens," laid 

 before tlie Botanical Society of Edinburgh, between 1853 and 1855, and pub- 

 lished in its 'Proceedings,' as well aa in the 'Edinburgh New Philosophical 

 Journal,' in 1854 and 1855. 



t Vide page 46. 



\ Especially those of Ilepp (Switzerland), Nyhinder (Franco), Dietrich 

 (Germany), Leighton and Mudd (England). 



