124 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
coating of 01. Ricini 3 vols., absolute alcoliol 2 vols., is laid on. In 
this way very large sections can be laid on evenly after smoothing them 
down by pressing on several folds of filter-paper. If now placed in 
absolute alcohol the strips come away, leaving the sections adhering. 
Many more details are given by the author as to the treatment of 
paraffin sections, but we have only space to indicate the more salient 
features of his procedure. 
(4) Staining and Injecting. 
Staining Nervous System of Insects.* — M. A. Binet has obtained 
his best results by using sublimate and osmic acid as fixing agents; 
•certain parts of the dotted substance take on a deep stain, under the 
influence of osmic acid, and this stain distinguishes them from other 
regions, and allows of the delimitation of certain important lobules. 
The best fluid in which to make a rapid dissection of the nervous system 
is the blood of the insect itself. Permanganate of potash will reduce 
sections which have been blackened too deeply by osmic acid, and care 
must be taken, as too long treatment will result in the complete trans- 
parency of the sections. 
Like others, M. Binet has found great use in corrosive sublimate. 
Pieces fixed with it may, after the method communicated to the author by 
M. de Nabius, be treated for a day with a 1 per cent, solution of sulphate 
of copper ; they should then be washed for six hours, and then stained 
for twelve in a solution of 0*05 gr. haematoxylin, 15 ccm. of absolute 
alcohol, and 25 ccm. of distilled water ; there should then be another 
bath of the same solution of sulphate of copper, and dehydration by 
various strengths of alcohol. 
Staining Nervous System of Embryonic Crustacea. t — Mr. E. J. 
Allen found that embryos of the Lobster were the most convenient for his 
purpose, as the fibres are coarser than in most embryonic Crustacea, and 
the thoracic ganglia can be exposed with comparative ease. He is in 
the habit of keeping a standard solution of methylen-blue of 1/10 per 
cent, in normal salt solution ; this is diluted with 15 or 20 volumes of 
a mixture of three parts of sea-water to one of fresh immediately before 
use. The staining is most satisfactory at a temperature of 20° to 25° C. 
The embryos are placed on a slide with the thoracic ganglia uppermost, 
and covered with methylen-blue solution. The process of staining 
may be watched under the Microscope ; no cover-glass should be used. 
The preparations may be fixed in a solution of ammonium picrate con- 
taining an excess of ammonium carbonate, and mounted in glycerin diluted 
with an equal volume of the fixing solution. They do not. appear to be 
quite permanent, and the best way is to examine a very large number of 
fresh preparations. In dealing with methylen-blue it must always be 
remembered that one cannot be sure that the whole of the element has 
taken up the blue. 
Staining of Myelin and Fat by Osmic Acid or Tannin. :J — Dr. L. 
Azoulay has tried to fix osmic acid on the myelin of nervous tissue or 
on fat, and then to reduce it by tannin or its analogues. To do this he 
* Journ. de l’Anat. et de la Physiol., xxx. (189-1) pp. 468-74. 
f Quart. Journ. Micr. Sci., xxxvi. (1894) pp. 461-4 ; 483-5. 
X Anat. Anzeig., x. (1894) pp. 25-8. 
