Collecting, Mounting, and Preserving Galls 19 



kinds do not alter very greatly. The succulent kinds, however, 

 shrivel quickly and lose their colour. It does not seem to be 

 possible to preserve their colours nor shape in any way com- 

 parable with their pristine condition. A few experiments with 

 fluids as preservatives show that methylated or even pure spirit 

 is of no value, as it extracts the colours. Pure glycerine, or a 

 mixture of equal parts of glycerine and water, is of little value. 

 Solutions of corrosive sublimate, and also of formalin, are not 

 always successful, for in many cases the leaf, the stem, or the 

 gall itself loses more or less of the natural colours, and then 

 the true value is deficient. 



