COLLECTING AND PRESERVING 305 



can be made by melting in a tin some paraffin wax, and 

 adding to it, as it melts, about one-fourth its weight of 

 pure indiarubber (old bicycle tyre is good). This can be 

 warmed and applied as required. 



A good supply of methylated spirit. (There are two kinds 

 of this : one which mixes with water to a clear solution, and 

 one which does not, but gives a milky turbidity. It must 

 be the first kind.) I mention methylated because it is 

 cheap, but rectified spirit mixes with water without risk 

 of turbidity. 



A bottle of Formalin (the ordinary commercial solution 

 of forty per cent, formaldehyde). 



A solution of corrosive sublimate (perchloride of mercury) 

 in water. This salt dissolves slowly and sparingly in water, 

 but an excess should be in the bottom of the bottle, which 

 can remain there, and water be added as the^supply of 

 solution is used up. 



A bottle of ether. 



Some card boxes of various sizes. 



Pins, forceps, scissors, knife, needle and thread, gummed 

 labels. 



Now the work. 



Foraminifera. These, being minute, will be dealt with in 

 the chapter on microscopic methods. 



Sponges. Those of which it is desired to make micro- 

 scopic preparations will also be dealt with in the next 

 chapter, but the specimens intended for the purpose must 

 be taken special care of as soon as they are gathered. 

 The best for study of histology are the small Calcispongia 

 (see p. 19), say Sycon. One specimen will be ample for 

 many slides, so select a nice clean one, and place it, pro tern, 

 in a shallow dish in clear sea-water (it will keep alive! for a 

 day or so), for future treatment, as on page 319. 



If coarser sections of the larger sponges, just^to show 

 the spicules, etc., are desired, cut out suitable portions 

 V 



