144 SYDNEY H. VINES. 



crackling noise. The fasciculi of the first order are dis- 

 tinguished by their aspect as well as by the great resistance they 

 ofler to the probe, which may need to be aided by a few strokes 

 of a knife. The fasciculi of the second order are distinguish- 

 able by their fineness and the readiness with which they break. 

 They may be further recognised on membranous layers which 

 have been entirely detached, and which, though apparently 

 smooth, give to the finger when lightly passed over the surface 

 the sensation of numberless points so closely set together as to 

 feel like a fine brush. Moreover, when vie\ved with a magnify- 

 ing power of 40 diameters, they are seen to be perpendicular to 

 the surface of the detached layer, whereas the broken ends of the 

 first order of fasciculi are not only larger, but lie flat on the 

 fibrous layer. 



I cannot doubt that the objects here described are really the 

 perforating fibres ; at the same time, I cannot well conceive that 

 those I have met with, small and soft as they are, should feel 

 under the finger like the hairs of a brush, however fine. 



Eespecting Dr. dementi's note, 1 have further only to point 

 out that he is in error when he asserts, as he does (p. 13), that 

 I did not notice the existence of the fibres in question in flat or 

 tabular bones ; and, in conclusion, I cannot help saying that 

 when I first observed these fibres I had no idea that they had 

 been recognized before, still less did I imagine that the subject of 

 my observation would ever acquire such importance as to lead to 

 a formal claim of priority on the part of Italian science. — Yours 

 faithfully, W. Sharpey. 



E. A. Schafer, Esq., 



Dec. 1, 1877. 



Recent Eesearches info the Nature of Lichens. By Sydney 

 H. Vines, B.A., B.Sc, Fellow and Lecturer of Christ's College, 

 Cambridge. 



In previous volumes of this Journal,^ Mr. Archer has traced 

 the history of the discussion upon Schwendener's theory from its 

 commencement in 1868 down to the end of the year 1873. I 

 ^vill endeavour to maintain the continuity by briefly alluding to 

 the principal papers which have appeared upon the subject during 

 the mterveniug years, reserving the more recent publications for 

 a somewhat detaded account. 



' Vols, xiii and xiv. 



