216 
treatment continued until the straw-colour of the spirit 
remains permanent. It may then be assumed that all 
the sublimate has been removed. The worms may then 
be transferred to fresh 90 per cent. spirit, and kept therein 
until required for sectioning. 
The segments required for sectioning are dehydrated 
by passing through absolute alcohol (three changes), and 
are then placed in either xylol or cedar-wood oil. The 
writer has found the latter very satisfactory, provided that 
care be taken to ensure the thorough removal of the oil 
when imbedding in paraffin wax. That is, the specimen 
is transferred from cedar-wood oil to the first vessel of 
wax and afterwards to a second and third, before finally 
imbedding. The time required in the bath, of course, 
depends on the size of the tissue, but for a piece say half 
an inch long by an eighth of an inch in diameter from 
2 to 3 hours would be sufficient, except in the case of the 
anterior end where a little longer time is desirable. Wax 
with a melting point of 56° to 58° C. is best for Arenzcola. 
The best results are obtained by staining the sections 
on the slide by means of iron-alum-hematoxylin. If 
this be too long a process the specimen may be stained in 
bulk (before cutting into sections) with borax carmine, or 
Mayer’s acid-hemalum. Some of the sections, especially 
those in which it is desired to show gland cells (e.g., in the 
stomach*) may, with advantage, be stained with Mayer's 
acid hemalum or with Grenacher’s or Delafield’s 
hematoxylin. 
Transverse sections are useful for the study of the 
general anatomy, alimentary canal, nephridia, &c.; 
sagittal sections of the anterior end are helpful in the 
* The histology of the alimentary canal of starved specimens 
should be checked by the study of sections of small pieces removed 
from a worm immediately after taking it from the sand. 
