474 F. P. SMITH ON THE MOUNTING OF SPIDER DISSECTIONS 



long period, and that it can, should the mount deteriorate, be 

 remounted without more trouble or risk than that involved in 

 the original process. In giving details as to how I usually pre- 

 pare such mounts I should like it to be understood that I lay no 

 claim to the method being anything revolutionary or novel ; and 

 I trust that my endeavour to make the process intelligible to the 

 tyro may be accepted with forbearance by the expert. We will 

 presume that a palpus of a male spider is to be mounted — say for 

 example that of the " garden spider " (Araneits diadematus). The 

 procedure is as follows. 



The spider when caught is killed by immersion in whisky. 

 Some one will probably ask, " Why not brandy?" There is no 

 reason except that when I commenced this work there happened 

 to be a bottle of whisky in the house and I purloined sufficient 

 for my first experiments. Finding it successful, I continued to 

 use it. Throughout these remarks it should be understood that 

 in almost every detail of the process now recommended numerous 

 variations in procedure might be proposed, often, perhaps, with 

 advantage. I merely suggest that the beginner should mount a 

 slide or two blindly following the instructions, and then work out 

 improvements for himself. 



If a preserved spider is to be dealt with, we remove the palpus 

 and soak it in whisky for an hour or so — this is, of course, pre- 

 suming that the specimen has been suitably preserved in methy- 

 lated spirit. We also obtain some glass slips with circular cells 

 about \ in. in diameter excavated in them, some tin cells of | in. 

 diameter and of various thicknesses, and cover-glasses to match. 

 The cells should be ground perfectly flat (not polished) upon each 

 side. This is easily accomplished by gluing a sheet of emery 

 cloth upon a smooth board, and rubbing the cell upon it by means 

 of a large cork or flat piece of india-rubber. Some of the thicker 

 cells should be ground, down to various degrees, for reasons which 

 will appear later. The slips must be scrupulously clean. Should 

 they be at all greasy a little liquor potassae will be found useful.* 



Mr. A. W. Sheppard tells me that a mixture of bichromate of potash 

 and sulphuric acid is the most perfect medium for cleaning glass. The 

 importance of theoretical cleanliness in work where the adhesion of cement 

 is a primary consideration cannot be overestimated. A piece of gelatine- 

 coated paper, which will stick like a limpet if placed wet upon perfectly 

 clean glass will, as every photographer knows, peel off the glass with the 

 utmost ease if the slightest trace of grease or even French chalk has been 

 applied. 



