PRESERVATION OF NAT. HIST. SPECI^rENS. 507 



A further difficulty is that paper in a damp climate, goes yellow and even- 

 tually brown ; that means an unsightly box or the removal of all the specimens 

 to a fresh box. We tried boxes containing no cork but paper stretched tightly 

 round one fixed and one adjustable bar but we abandoned these. If one could 

 get a permanently white surface, without paper, it would be a boon. 



We will not describe the various devices we have tried but will go straight 

 to the final product ; every possible device that suggested itself was tried 

 culminating in the following : — 



An ordinary teak store box is used, without cork in, well varnished inside 

 top and bottom ; a sheet of cork matting slightly smaller than the bottom, is 

 cut ready, painted white on one side and dried ; a mixture of hard paraffin. 

 80 per cent, (melting point 55-(50°C)and napthalin 20 per cent, is melted, the 

 paraffin first ; it is poured into the box and tlie cork sheet put down and 

 carefully smoothed out, so as to get the hot liquid over the cork sheet, and so 

 as to leave no air below the cork, this sets hard very soon and before or as it 

 does so, more melted paraffin — naphthalin is poured over and allowed to set in 

 a smooth even sheet. To whiten this layer completely the cork sheet is first 

 painted white and allowed to dry. This gives an even dead-white surface, 

 which may be kept smooth by the application of a warm roller or smooth 

 metal surface ; a solid sheet of this paraffin is not good for pins as it has no 

 elasticity ; but by embedding the cork in it, the elasticity of the usual box is 

 retained, with the advantages of a hard napthalined surface which oflers no 

 harbourage to psocids or beetles. In addition, the sheet of solid paraffin goes 

 far to prevent waiping and to make the box air tight. No paper is used in the 

 box at all ; there is a well varnished lid, air tight and offering no harbourage 

 to insects, the smooth sheet of paraffin is impervious to insects and fills in all 

 the crevices, and the only harbourage for Psocids is where the lid falls on to 

 the box. 



The actual weight of one of our boxes with cork and without paraffin is 

 2,050 grammes ; the paraffin added weighs between 350 and 400 grammes. 

 This excessive weight is the one drawback ; it is practically unavoidable if 

 a stout teak box is used at all. the paraffin only increasing it by 20 per cent. 



The addition of creosote to the paraffin has been tried and abandoned since 

 it produces a less white surface. 



Psocids, on dried insects from an infested cork box, put into one of these 

 paraffin boxes die within 24 hours and may be found on the floor of the box : 

 it is actually unnecessary to poison such a box in any way at all and we use no 

 cells or napthalin. Our boxes have not been in use long enough for us to be 

 able to definitely recommend them for adoption ; the cold here is at present 

 considerable, a minimum of 43° F. outside and 60° F. in the laboratory, but 

 the paraffin is not too hard. We have not yet tested the boxes in a tempe- 

 rature over 105° F. and it is possible that when the temperature rises over 

 il0° F,, the specimens may develop grease or some other untoward thing 

 happen. So far as our present experience goes, the boxes are admirable, 



