WORMS 377 



alcohol being increased on each occasion. In the 

 course of ten or fifteen minutes the worms will be- 

 come motionless and limp, and will show no move- 

 ment on being touched. They are then taken one at 

 a time from the sea water, and laid upon a dry glass 

 plate, on which they are stretched out with the help 

 of two camel-hair brushes. In this position they are 

 killed with formalin-spirit (70 per cent, alcohol, 100 

 volumes ; formalin 40 per cent., 5 volumes), placed on 

 them by means of one of the camel-hair brushes, only 

 enough being used just to surround the worm, without 

 running over the glass plate. If the worms contract 

 or become slightly contorted when the formalin- 

 spirit is first added, as they generally do, they should 

 be straightened out with the brushes, and held in a 

 suitable position until they begin to get hard. After 

 a few minutes on the glass plate they will become 

 sufficiently hard to be removed to a flat-bottomed dish 

 containing formalin-spirit, in which the fixing process 

 should be completed. In practice one may have a 

 considerable number of the worms on the glass plate at 

 the same time, continually moving some to the dish 

 of formalin-spirit, and taking fresh ones from the sea 

 water. 



After being in the flat-bottomed dish for some hours, 

 the worms may be transferred to tubes, and stored 

 permanently in formalin-spirit. 



Aphrodite and Hermione are killed well extended if 

 placed in fresh water for ten or fifteen minutes. 



For histological work, Hermann's fluid, Flemming's 

 fluid, and corrosive sublimate-acetic acid mixture, give 

 good results. The worms should be killed by adding 

 alcohol to the sea water, and the first stage of hardening 

 should be carried out on a dry glass plate in the way 

 above described, Hermann's fluid, etc., being used 



