570 
SUMMARY OF CURRENT RESEARCHES RELATINO TO 
be rocky, it is hardly possible at all. No doubt, when the method 
comes to be more largely used, improvements and alterations will be 
made in it. 
New Steriliser.* — In this apparatus a double-walled steam cylinder 
effects a constant temperature of the interior. The heating is accelerated 
by the bottom of the apparatus being bent inwards, so that the water 
above the flame is only a few centimetres in depth. The main mass of 
the water is in a ring-shaped enlargement of the lower part. 
Formic Aldehyde Lamp for Disinfecting Purposes.f — The firm of 
G. Barthel, Dresden, have brought out a new formic aldehyde lamp. 
In the lamp methyl-alcohol is drawn up into a tube by a wick, is eva- 
porated, and burnt with a limited supply of air. 
(2) Preparing- Objects. 
Method of Preparing Molluscan Eggs.f — Mr. J. Fujita, in his 
experiments on Molluscan eggs, studied the normal methods of develop- 
ment, thus : — The eggs were stained in toto, and passed through ascend- 
ing grades of alcohol as usual ; on a prick being made through the 
chorion, the eggs were set free into the alcohol. The latter was then 
immediately replaced with clearing fluids, and the eggs were afterwards 
mounted in balsam. This method is quite sufficient for tracing all the 
history up to the formation of the mesoderm. For the purpose of 
experiments the method employed resembled generally that adopted by 
Crampton. The eggs were first examined with a low power to determine 
the stage to which they had developed. The separation of the blasto- 
meres was at first attempted by the use of very fine needles, but, as the 
blastomeres are minute in size, the author failed in almost every case, 
and, even when successful, the rough treatment resulted in death. At 
last the difficulty was got over by trusting to the accidental separation 
of the blastomeres in the breaking and piercing of the gelatinous enve- 
lope and the chorion ; the egg fragments thus obtained were transferred 
to watch-glasses by a jet of steam, and were then ready for observation. 
Examination of Polar Rings of Earthworms.§ — Miss K. Foot, after 
trying various reagents and stains, made use of lithium-carmine and 
Lyons’ blue. The method that has proved most satisfactory for eggs of 
Allolobojohora foetida is to stain the sections from one to twenty-four 
hours in lithium-carmine, wash in acidulated alcohol for a few seconds, 
and double stain with a very dilute solution of Lyons’ blue. The 
process must be carefully watched under the Microscope. If the stain- 
ing be properly modified to suit the special fixative, all the fixatives 
tested give results more or less satisfactory, but the corrosive sublimate, 
with or without acetic acid, gives the most brilliant and satisfactory 
reaction. However, Miss Foot thinks that the most reliable fixative is 
chromo-acetic, for it so fixes the eggs that the subsequent treatment with 
alcohols produces scarcely perceptible shrinkage ; with its use all the 
structures of the cell may be constantly and sharply defined. The 
* Centralbl. f. Bakteriol. u. Parasitenk., l t0 Abt., xviii., No. 25. See Zeitschr. f. 
ang. Mikr., ii. (1890) p. 108. f Zeitschr. f. ang. Mikr., ii. (1898) p. 109. 
X Zool. Mag., viii. (1896) p. 49. § Jouru. of Morphol., xii. (1896) pp. 3-8. 
