362 PRESERVATION OF MARINE ORGANISMS 



put in. Even then it is liable to slip up, especially if 

 the tube contains alcohol. There is always an un- 

 certainty with corked bottles. They are safe for short 

 periods up to about twelve months, and after that 

 they should be examined at least once a year. The 

 risk of leakage and evaporation can be considerably 

 reduced by coating the cork with paraffin wax, and 

 this should always be done before finally storing away 

 the bottles. The method is quick and simple, and 

 the gain in security is well worth the trouble. It is as 

 follows : 



After corking, wipe the top of the cork and the rim 

 of the bottle, and then place the bottle aside for a 

 day, or longer, to dry. It is very important that the 

 cork should be perfectly dry, and no fluid in the 

 crevice between the rim and the cork. When the 

 bottles are ready for coating, melt some hard paraffin 

 wax (paraffin wax candles or any kind of hard wax 

 may be used) in a small metal pot. A gluepot is a 

 great comfort for this purpose on board ship ; it can 

 be stood on the galley-range. Then dip the cork 

 deep enough to cover about a quarter of an inch of 

 the glass. After the first coat has solidified and 

 cooled, give a second dip, quickly in and out, or else 

 the first coat will have time to melt off. A bottle or 

 tube properly sealed with paraffin wax will stand 

 against evaporation for several years. Some bottles 

 and tubes recently examined after being stored away 

 for eight years were quite sound ; but a few showed a 

 slight loss of fluid, though the paraffin coating was 

 externally flawless and perfect. On further examina- 

 tion it was found that the paraffin was no longer 

 adhering to the glass. 



Miniature bottles, with a capacity of about J ounce 

 (15 c.c.), made of thin glass and fitted with a good 



