Ne (EA 
ment the alimentary canal will contain very little sand. 
This can usually be ascertained by examining the worms 
by strong transmitted hght, when any sand present in the 
gut will be detected. As soon ag all the sand has been 
voided the worms may be placed in a dish containing a 
smaller quantity of sea water. They may then be 
narcotised by dropping absolute alcohol little by little on 
to the sea water until the liquid contains about 5 per cent. 
of aleohol. After a few hours the worms will be sufficiently 
narcotised and may then be killed in an extended 
condition. Before attempting to kill them ascertain by 
touching them if they are thoroughly narcotised. Care 
should be taken not to allow the worms to become quite 
dead in the alecoholised sea water, as the tissues sufter. 
A good killing and fixing mixture is sublimate acetic 
(95 parts saturated sublimate solution and 5 parts glacial 
acetic acid). Ags soon as the worms are dead transverse 
incisions” should be made in the body wall at intervals of 
+ to ? inch, so as to allow the re-agents to penetrate 
rapidly and fix all the internal organs. If the operations 
above described be carefully carried out the worms will 
be killed straight, a great convenience when sectioning. 
After a few hours in sublimate acetic the worms are 
washed in running (fresh) water for a few minutes, and 
then transferred to 50 per cent. alcohol (two or three 
hours), to 70 per cent. and to 90 per cent. alcohol (two or 
three changes). ‘To the latter a few drops of tincture of 
iodine should be added to dissolve from the tissues of the 
worm the last traces of sublimate. Fresh iodine should 
be added as the liquid becomes decolourised, and this 
** This should be done as rapidly as possible, as on contact with 
metal a deposit of mercury is liable to be formed in the tissues. The 
worms should be transferred from one vessel to another (where that is 
necessary) by means of glass, horn, or paper lifters, and all contact 
with metal avoided. 
