1885, ] Muroscopy. 1137 
the epidermis. At thetime of hatching, long before the eyes and 
segmental sense-organs appear, two pairs of these sense-bulbs 
are found, symmetrically placed on the surface that is to form the 
margin of the lip. The symmetrical arrangement in pairs, the 
second pair being a little behind the first and farther apart, sug- 
gests that these organs were primarily strictly segmental.—C. O 
Whiuman. 
REPAIRING BALSAM PREPARATIONS.— When balsam preparations 
have been made with a very thin solution, or with a small amount 
of fluid, evaporation sometimes causes the balsam to be invaded 
by air spaces which it is difficult to refill, even witha thin solution 
of balsam. Such spaces may readily be filled with the solvent of 
the balsam (benzole), and then a drop of thin balsam placed at 
the edge of the cover glass will gradually replace the benzole as 
it evaporates, without leaving air spaces. To prevent a too rapid 
introduction of the benzole, it is desirable to transfer it with a 
glass tube drawn to capillary fineness at one end, rather than with 
a glass rod. If the tube is not too large—5 or 10™"—and is 
drawn out quite gradually, enough benzole may be sucked into it 
to serve for repairing a large number of slides without danger of 
loss by its running out or by evaporation when the tube is laid 
down. The application of the capillary end of the tube to the 
edge of the cover glass induces a steady and even flow of the 
fluid, until the space beneath the cover glass is completely filled. 
—E£, L. Mark. 
Tue Eves oF ANNELIDS.'"—For the study of these small eyes 
it is necessary to make very fine sections and to remove the pig- 
ment. The decoloration of the eye may be effected by soak- 
ing in glycerine, to which a little 35 per cent caustic pot- 
ash has been added. When the work of decoloring has been 
carried sufficiently far, it should be checked by neutralizing with 
dilute hydrochloric acid ; and then the preparation should be care- 
fully washed before transferring to a hardening or mounting 
fluid. The preparations are best preserved in glycerine. 
A New Sotvent oF CuitT1n.—In a previous number of “ Mi- 
croscopy ” I have called attention to the use of hypochlorite of 
potassium (KCIO), or Eau de Javelle, as an agent for removing the 
soft parts of such animals as Spongilla, and for preparing skeletons 
of small animals. Dr. Looss? now recommends this fluid and the 
corresponding combination with sodium (NaClO) as excellent 
‘solvents of chitin. The thickest and hardest chitinous parts of 
insects, after soaking long enough to become transparent and per- 
fectly colorless, may be quickly dissolved by boiling in one of 
these agents. 
If the commercial fluid is diluted by adding 4-6 times its volume 
1 Graber, Archiv. f. mikr. Anat., XVII., p- 250, 1879. 
2 Zool. Anzeiger, VIH, No. 196, p. 333, June, 1885. 
