DRY MOUNTING. 



295 



from the potato, should be well washed from all foreign 

 substances, and mixed with cold distilled water, so as to 

 form a slightly opalescent liquid A thin glass cover 

 having been cleaned is breathed upon, laid level upon the 

 table of the desiccator (Fig. 238), and a drop of the 

 starch solution deposited upon it. When perfectly dry 

 it may be coated at the edges with brown varnish, and 

 inverted upon a shallow varnish cell, as has already been 

 described for diatoms, and finished in the same manner. 



Such specimens as micro-fungi, Penicillium glaucum (/), 

 P. roseum (n], Ascophora mucedo (/), P. chartarum (/), 

 Aspergillus glaucus (m), Fig. 241, can only be successfully 



FIG. 241. 



mounted by the dry method, as when mounted in fluid the 

 spores become detached, and the chief characteristics are 

 lost. 



The best way to mount such specimens would be to 

 choose a cell deep enough to hold them comfortably, and 



