1901) MICROSCOPICAL JOURNAL. 281 
corners of the cover-glass, or prying up the cover-glass, a 
little at one or more corners with the point of a scalpel. 
If the specimen is a worm, it will contract at first; but 
afterwards will usually become fairly extended. After 
two or three hours the worm, although still living, be- 
comes almost perfectly quiescent, A few drops of a 4 per 
cent solution of formaldehyde are then run under the 
cover-glass, its flow being hastened by draining away 
with bibulous paper an equal quantity of water at the op- 
posite side. The worm should die in a fairly extended 
condition. A sufficient quantity of formaldehyde should 
be run under to displace all the sea water. After an hour 
or so the gradual replacement of the formaldehyde with 
glycerine may begin. Mr. Johnson has always used un- 
diluted glycerine, but suggests that a mixture of equal 
parts of glycerine and water might be safer for very deli- 
cate objects. The glycerine is applied in the same way 
as the formaldehyde, but more gradually—only two or 
three drops at a time. After the specimen has become 
completely surrounded and permeated with pure gly- 
cerine, the mount is sealed with Venice turpentine in the 
manner explained in Lee’s ‘‘Vade Mecum,” fifth edition, 
p. 291. 
The preparations will keep almost indefinitely without 
sealing, but with the obvious disadvantages that the gly- 
cerine is likely to flow over the slide in moist weather, 
and a mist gathers on the cover-glass. The preparation 
should be flat at all times. This method has been found 
to meet all the requirements of the case for small Anne- 
lids and Echinoderms, and would probably be equally 
successful for a wide range of minute animal forms, ex- 
cepting always those with impermeable chitinous integu- 
ments, like the Arthropods. Syllidae and other small 
Polychetes up to a length of four or five centimetres have 
been successfully treated, and preparations made three 
years ago are as beautiful and instructive as at first. 
