1895 THE MICROSCOPE. 43 



March, kindly pre])ared by our assistant, L. W. Willson, who 

 is in charge of the Department of Practical Suggestions. 



Where to Hunt Lichens. The following data are com- 

 piled chiefly from the Encyclopaedia Britannica, 9th Ed. 



Lichens are never found on cultivated ground nor in atmos- 

 phere impregnated with smoke. They demand a quiet and 

 exposed situation. 



1. The rugged bark of old trees. (Raraalina, Parmelia, 

 Stictei.) 



2. The smooth bark of young trees and shrubs. (Graphi- 

 deus, Lecidea.) 



3. Trees by roadsides (Physcia) or in large forests. (Usnea, 

 Alectoria.) 



4. Decayed wood of trees and old pales, (Calicieus, Leci- 

 dea, Xylographa.) 



5. Calcareous and cretaceous rocks. (Lecanora, Lecidea, 

 Verrucaria.) 



6. The mortar of walls. (Lecanora, Lecidea, Verrucaria.) 



7. On calcareous, peaty, and argillaceous soils, and on har- 

 dened mud. (Cladonia, Lecidea, Lecanora, Collema, Peltidea.) 



8 The sands of sea-shore and the granitic detritus of lofty 

 mountains. 



9. On decayed mosses and moss-like plants. (Leptogium. 

 Gomphillus.) 



10. Upon perennial leaves of certain trees and shrubs 

 (Lecidea, Bouteillei, Strigula.) 



11. On tombstones, old leather, iron and glass, on the 

 bleached bones of reindeer and whales, on the dried excrements 

 of sheep. 



12. Parasitical upon other lichens. (Lecidea, Pyrenocarpei.) 



QUESTIONS ANSWERED. 



NoTB. — Dr. S. G. Shanks, of Albany, N. V. , kindly consents to receive all sorts of ques- 

 tions relating to microscopy , ivhethe> asked by professionals or aviatrurs. Persons of aU 

 f ades of experience , /ro»i the beginner upward, are ivelcume to the benrjits </ thts drpar* 

 nient. The questions are numbered for future > e/erence. 



221. Is there any good work containing the classification of Bac- 

 teria and descriptions of methods of cultivating them f 



