BY THOS. STEEL. 575 



Formaline solution made by diluting 3 volumes of the strong- 

 formaline of commerce to 100 volumes with water, has proved an 

 admirable preservative, and has the great advantage of not 

 coagulating the slime like spirit. In a general way, however, I 

 prefer the latter medium, as on the whole the results attained 

 when it is properly used seem to me rather the more pleasing. 

 Though formaline in some cases induces rather more colour 

 change than spirit, and is a somewhat disagreeable medium when 

 the specimens have to be much handled during examination, it 

 may be used with confidence if preferred. When the specimens 

 have to be preserved in the field, or the collector is unable to do 

 more than put them direct into the preservative, formaline should 

 be used. It should not be made any stronger than indicated 

 above, and should be used plentifully. 



In preserving these worms — and I may here state that earth- 

 worms, leeches, and slugs may be treated in precisely the same 

 manner —I first of all kill them with weak spirit. The strength 

 which I prefer is 1 of ordinary methylated spirit to 15 of water. 

 The worms are dropped into plenty of this contained in a shallow 

 dish, and die in 10 to 15 minutes without the slime becoming 

 coagulated, or the worm becoming distorted or broken. I now 

 take them up one at a time by means of a pair of weak-springed 

 fiat-bladed forceps, and with the aid of a damp cloth and my 

 wetted fingers gently draw the blades of the forceps along the 

 worm's body, slightly compressing the body between them, and 

 in this way scrape off the slime, wiping the forceps on a piece of 

 rag. With a little care this can be done readily and safely even 

 with the most delicate planarians, and leaves them beautifully 

 clean and free from the objectionable slime. It is necessary to 

 keep the fingers moist, otherwise the worm will stick and become 

 damaged. 



Having the formaline or strong spirit (80 to 85 per cent.) in 

 another shallow dish, the worm is gently laid in it, and by means 

 of fingers and forceps flattened and straightened out and pre- 

 vented from shrinking too much as the spirit hardens it. A few 

 moment suffices for this, and it is now left while the others are 



