800 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The insects are immersed for two days in an alcoholic solution of 
naphthaline, and are rapidly desiccated by heat. Sometimes a little 
touching up with brilliant anilin-azure and alcoholic tincture of cur- 
cuma is advisable. For the refinements of the author’s method the 
original paper must be consulted. 
Embryology of Echinocyamus.* — Dr. Theel did not succeed in raising 
larvm of Echinocyamus pusillus to the stage of the young sea-urchin till 
he adopted the following precautions. The aquaria ought to be of a 
capacity of 30 litres or more, rather high, made altogether of glass, and 
be covered in. Clean marine plants in sufficient number must grow in 
the water. The water itself must be cautiously stirred with a glass rod 
several times a day, and no film must be allowed to form on the surface. 
All the water used must be fetched from the open sea and filtered 
through cloth or the finest canvas. The foul matter from the bottom 
must be taken away every other day. The temperature ought not to be 
too high, or, in other words, the aquaria should not be placed in sunny 
rooms. 
The form of moist chamber preferred by Dr. Theel is that in which 
the drop of water is slightly pressed between the slide and the cover- 
glass ; compression of the eggs may be prevented by small particles of 
wax, and evaporation hindered by fixing the cover-glass with melted 
paraffin or wax. In such chambers the author succeeded in following the 
gradual changes in the development of the same egg for several days. 
There is no difficulty at all in artificially fertilizing the eggs of this 
animal if care be taken to choose males and females accustomed to live 
under similar conditions. 
Preparation of Sections of Protozoa.t — Mr. J. E. S. Moore killed 
specimens of Sjpirostomum by osmic acid or by heating, fixed them 
in Flemming’s or Hermann’s solution, and, after 12 to 18 hours, 
transferred them to a tall tube, from which the supernatant liquid was 
repeatedly decanted and replaced by distilled water for some hours. 
After the last filling up the water was poured off and alcohol added 
very gradually until a 50 per cent, solution was obtained ; in this the 
infusoria remained, like a coarse precipitate, for 12 or 18 hours more. 
The strength of the spirit was then increased until the whole was 
gradually replaced by absolute alcohol. After treatment with cedar oil 
or chloroform the objects were transferred to paraffin. 
(3) Cutting:, including- Imbedding- and Microtomes. 
Method of Fixing and Imbedding Tissues for the Rocking Micro- 
tome.:]: — Mr. J. H. Mummery, in giving a demonstration at the Annual 
Meeting of the British Dental Association, gave the following lucid 
directions for preparing tissues for the microtome : — 
“ By ‘ fixing ’ two things are implied : — 
(1) The rapid killing of the element, so that it may not have time 
to change the form it had during life. 
* Nova Acta Keg. Soc. Upsala, xv. 1 (1892) vi. pp. 3-6. 
f Journ. Linn. Soc. Lond., xxiv. (1893) p. 365. 
% Journ. British Dental Assoc., xxiv. (1893) pp. 489-90. 
