DAMP AND MILDEW. 231 



and that there was an efflorescence about the montli, or that 

 mildew had appeared. My answer has ever been : 



Firstly, that possibly the specimen had been cased up too soon. 

 At least two months should elapse after stuffing before mammals 

 should be mounted in a case. 



Secondly, that common alum had been used instead of burnt 

 alum. 



Thirdly, that an undue proportion of saltpetre had been 

 mixed with the alum. 



Should mildew make its appearance, it would point to improper 

 mounting — i.e., not trimming ofO enough flesh or fat, or to the 

 specimen being mounted in a case before it was sufficiently 

 dry. If it be mildew, the specimen must come out of the case 

 and be properly dried. If it be merely crystallisation of impure 

 alum, the crystals must be washed off with warm water from 

 time to time as they form, until no more appear. It must be 

 rememberecl, however, that a damp house, or juxtaposition to a 

 wet wall, will ruin the most carefully mounted specimens. 



Correspondents may be quite sure that neither the method 

 nor the formula are to blame in the matter. The great point is 

 to wipe oif the mildew or crystals as fast as they appear until 

 no more form, which will determine when the specimen is 

 thoroughly dry. 



How to solder, either by the blowpipe or by the " bit," is now 

 and then useful knowledge. Any mechanic will impart this for 

 a consideration. 



