-490 Journal of Applied Microscopy 



No. 33. — Please describe how in a room for developing — with window cov- 

 ered with an extra sash of red and yellow glass in upper and lower sash — ven- 

 tilation can be secured in summer and not admit the light. v. a. l. 



No. 34. — Will some resident in Chicago kindly give some directions as to 

 where to seek biologic material — preferably on the north side district ? I under- 

 stood the park tanks were very prolific in micro forms, etc., but from whom should 

 permission be obtained to study the infusoria, diatoms, etc.? The local society 

 not being in existence any more, new residents are not up to the fauna localities. 



B. K. T. 



ANSWER TO QUERY 25, JUNE, 1902. 



Ferns show a great variety of scales, sufficient to give the student occupation 

 for a long time. On the underside of the leaves are the reservoirs for the spores, 

 resembling green velvet, arranged in stripes, masses, and various other forms. 

 The spores are usually covered by a thin skin and their manner of arrangement, 

 changes and developments are an endless study, different ferns giving us many 

 variations in this respect totally invisible without the microscope. The hymeno- 

 phyllums (of which two only, I believe, belong to England) are particularly inter- 

 esting. The leaf structure when dried makes them beautiful objects, often 

 requiring no balsam to aid in translucency. Portions of the fronds of ferns 

 should be mounted as opaque objects, after having been dried between blotting 

 paper — avoid pressure. The time of gathering is an important factor, as they 

 do not show their beauty before they are ripe, and if over-ripe the spore arrange- 

 ment, etc., is altered. I find a preferable way to mount objects is one in which 

 they can be studied as opaque or transparent when so desired. The spores 

 can be mounted separately like pollen. Carefully pick and let dry in a moder- 

 ately warm place in a pill box to keep free from dust ; mount dry in a cell with 

 a ring to hold the cover-glass up. Then coat over both ring and cover with 

 gold size or brown varnish. 



The under side of many ferns is covered with scales of very beautiful forms. 



Fronds are mounted in rings as above described, and it is best to mount in 

 various ways. The transparency from balsam interferes with one property of 

 the object, and yet develops another which would have remained invisible if 

 preserved dry. Many prefer the lieberkuhn for illuminating opaque objects ; 

 others place the slide on a wooden slip to make it opaque or transparent as 

 desired ; others again, by putting upon the under side of the slip, directly under 

 the object, a spot of black varnish, which does not interfere materially with the 

 light ; by using some such method, space is reserved in one's cabinet. The 

 lighter specimens can be mounted dry, the darker kinds in balsam. Staining 

 can also be done if desired, magenta being one of the best vegetable stains. 



The polariscope also aids in studying the forms of sori. To watch the develop- 

 ment of the spores of ferns and the fertilization and products, the late Dr. 

 Carpenter gave the following : Let the frond of a fern whose fructification is 

 mature be laid upon fine paper with its spore bearing surface downwards ; in a 

 day or so the paper will be found covered with a very fine brownish dust, which 

 consists of the discharged spores. Collect carefully ; spread upon the surface of 



