IN BRYOLOGICAL WORK. 523 



aid of a good lens. The inevitable result is that the micro- 

 herbarium becomes increasingly more important to the systematic 

 bryologist. 



The collection of slides the Quekett Microscopical Club has 

 done me the honour of accepting is fairly representative of the 

 kind of slide useful to the bryologist, although I have, in the hope 

 of proselytising amongst the members, made it more popular than 

 would otherwise have been the case. There is no question of 

 making attractive mounts with the bryologist, even if mosses lent 

 themselves to such a proceeding. By the time the modern 

 student of mosses has decided whether some moss is a sub-species, 

 variety, form, or hybrid of a certain species, he is usually beyond 

 the ambition of making an attractive mount of it, and merely 

 desires to see it safely under a cover-glass for future reference. 

 From the student's point of view the collection would undoubtedly 

 have been of far greater usefulness had it consisted of series 

 showing varietal differences in such difficult forms as exist 

 amongst the Harpidioid Hypna, but the general interest of such 

 a collection would have been nil. The casual excursionist into 

 the moss world is more concerned with general impressions than 

 varietal distinctions, and the microscopist who values his whole- 

 some outlook on Nature will leave such sections as the Harpidioid 

 Hypna to its creators. 



To the confirmed microscopist I fear the class Musci can never 

 be very attractive, as it is difficult, except in a limited degree, to 

 obtain clean, immaculate slides. The cleaning of such species as 

 Fissidens exilis, Pottia minutula, etc., which not only live on 

 tenacious clay formations, but succeed in covering themselves 

 entirely with it, is appalling if conscientiously carried out, and 

 usually quite fruitless, as by the time the clay has been removed 

 the specimen is in fragments and not worth mounting. Hence 

 cleanliness is next to uselessness in bryological work, and a really 

 useful collection of moss slides occupies a debatable position 

 between the geological and botanical kingdom i. I mention this 

 in case your Hon. Curator is puzzled as to which kingdom some 

 of the slides are intended to represent. A coi siderable amount 

 of soil usually adhering to the specimens may be got rid of by 

 prolonged soaking, repeatedly changing the water, and very 

 considerable help is got by strongly acidulatiag the water with 

 hydrochloric acid ; especially is this the case in calcareous 



