626 Journal of Applied Microscopy. 



covered unit-boxes fitted to covered trays of the size of an ordinary herbarium 

 sheet, and about one inch deep. Our boxes are of such size that sixty-four of 

 them fill a tray. It may be convenient to have some of the boxes of double size, 

 of double length or width. In these covered boxes, small pieces of the slirtie 

 mould-bearing material may be fastened securely with glue. The material 

 should be so placed in the box that it can be examined with a microscope. To 

 this end the sporangia must be raised as high as possible, just so that the box-lid 

 in closing will not touch them. It is sometimes well to mount some of our 

 material in such a way that the sporangia may, by the microscope, be examined 

 from one side. Such specimens should be attached to the side of the box, 

 projecting inward. Mr. Lister, author of " The Mycetozoa," prefers fastening the 

 specimens to pieces of rather stiff paper of such size that with the ends bent up 

 a little they just fit inside the box. It is thought that by this arrangement the 

 specimens may be more easily handled, lifted about to the instrument, etc. 



But it is time we should bring our material under the lenses. In case of 

 many species it is desirable to view the sporangia as dark objects, to study the 

 surface, measure the diameter, etc. Under a low power some species are well 

 worth such examination simply for their beauty. No natural objects are finer so 

 examined than some of the Lamprodermas, Diachaeas, or Badhamias ; all these, 

 aside from elegance of form, exhibit luster or iridescence. But to discover 

 structure we must generally resort to other views, other methods of preparation ; 

 indeed, we need all the light obtainable from any or every method. Various 

 forms of the Stevionitacece are well studied as dry mounts. In no other way can 

 one obtain so good an idea of the structure. A dry mount may be prepared as 

 follows : take a bit of rather stifi: Canada balsam the size of a pin-head, and 

 place it in such position on the slide that it will at some point meet the edge of 

 your circular cover-glass when laid on well centered. Now lay a single sporangium, 

 which may be detached under the dissecting microscope, over the center of the 

 slide and cover gently, allowing the edge of the cover to touch the bit of balsam 

 as provided. If skillfully done, the amount of balsam will be sufficient to hold 

 the cover firmly, but not enough to run under or at all interfere with your 

 specimen, which may now be examined with great advantage — every part in 

 natural position and condition. When the balsam hardens, the specimen with 

 proper handling will last indefinitely. 



For immediate microscopic study I find nothing better than to wet the 

 sporangium on the slide with a little alcohol, then with a weak solution of 

 potassic hydrate. To the preparation glycerine may be added if desired. This 

 will expand all the structures, and give remarkable clearness. Unfortunately 

 this also softens the delicate structures, so that a slight movement of the 

 cover-glass will destroy the preparation. For permanent mounts nothing is better, 

 in my experience, than glycerine jelly. As a preparation, Hantsch's fluid may 

 be used. Care must be taken, in all cases where potash is used, that the solution 

 be not strong, otherwise the delicate tissues are liable to shrivel or be consumed. 

 In some of the Hemitrichias the alkali solutions are apt to produce twisting of the 

 capillitial threads to such an extent as to interfere with satisfactory work. In 

 such cases the capillitium may first be drawn out in water, or water and glycerine,. 



