88 



cultivated plants [vide Carpenter, Prac. Ass. Econ. Biol., 

 Vol. I., Pt. I., July, 1905). Dr. Traquair (Beport to the 

 Plans and Worlcs ('oinin/ft/e of the Edinburgh T'own 

 Council, March, 100(i ; and The Scotsman, March 2ud, 

 190G) has recently dealt with the occurrence of Collembola 

 in hydrant boxes and water cisterns in Edinburgh. 

 Although the presence of these insects in such situations 

 is in itself harmless, the abundance in which they 

 were found is evidence that they find an ample food 

 supph' there, and herein lies the danger, for it points to 

 the water being contaminated. 



Note on Histological Techmque, &c. 



Specimens of Anurida are best collected from off the 

 rocks and weed by means of a camel-hair brush, and 

 transferred into a phial containing TO per cent, spirit ; 

 if it be desired to obtain them in large numbers, they can 

 frequently be scooped up in quantities from off the surface 

 of the tide-pools, using for the purpose a metal spoon or 

 some similar instrument. 



The mouth-parts and sense organs can be easily 

 studied by treating the head with a weak solution of 

 potassic hydrate, which, by dissolving the soft parts, 

 renders it gradually transparent. This should be 

 performed on a slide, under the lower power of the 

 microscope, and the action of the alkali checked, as soon 

 as the mouth-parts assume a pinkish-violet, by running in 

 alcohol under the cover-glass. 



If it be necessary to preserve the animals for histo- 

 logical purposes, they are best brought away alive in a 

 vessel containing sea water, and then transferred with a 

 camel-hair brush into hot TO per cent, alcohol, and after- 

 wards passed into that of 90 per cent, strength. Hot 

 corrosive sublimate or picro-sulphuric acid can also be 



