1899J MICROSCOPICAL JOURNAL. 14 



o 



forceps, a few needles and a bottle of Dean's medium. In 

 very many cases it is sufficient to pick off a small por- 

 tion, say of a pustule of Puccinia, and place it in a drop of 

 water, put on the cover-glass and flatten out, moving the 

 glass to separate the spores, when the main character- 

 istics will be easily made out. To get an idea of the en- 

 tire structure, and its relation to the nidus on which it is 

 growing, a section of the leaf should be made. This can 

 readily be done by placing the leaf in a slit piece of elder 

 pith, and cutting both leaf and pith with a sharp razor. 

 With a little practice it will be found that fairly thin 

 sections can be made without much difficulty. The asci 

 and sporidia of the Sphseriacei may be obtained by crush- 

 ing the conceptacles under the cover-glass. Moulds of 

 the Aspergillus nature are not so easily dealt with. Their 

 spores are attached very loosely, and the whole character 

 is dependent on the attachment and grouping of these. 

 Hence, if placed directly in water, the spores would be 

 washed away, and the specimen become valueless. This 

 difficulty can be overcome in a great measure b\ T placing 

 the piece intended for examination on the glass slip dry, 

 adding a drop of absolute alcohol or acetic acid, and then 

 a drop of Dean's medium. If glycerine jelly be used, 

 the alcohol sometimes precipitates the gelatine in a cloudy 

 form, but with Dean's medium there is less trouble, and 

 the alcohol gets rid of air bubbles, which are otherwise 

 very annoying. In specimens mounted without alcohol, 

 bubbles can be got rid of by boiling gently over a spirit 

 lamp, but this cannot be done with moulds. When the 

 specimen is not wanted permanently, a mixture of glyce- 

 rine and water makes a good temporary mountant; in 

 this it will remain for along time without drying up. 



I now propose to give a very brief outline of a few of 

 the principal groups of Micro-fungi. 



Uredineae and Ustilagineae. — These are the Rusts, 

 Brands and Smuts which are found on corn and manv 



