602 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is pressed by tlie screw s of the clamp, after the clamp has been attached 
by means of the screws e. The double knife made by Walb,* and the 
section-stretcher of Prof. Born,'f are also described. 
Electrical Phenomena of Paraffin Sections.! — Dr. G. C. van 
Walsem directs attention to certain electrical phenomena which occur 
when making paraffin ribbon sections. Occasionally, when the strip of 
section is being removed from the band, it is strongly attracted to any 
larger object, such as the microtome itself, the table, or the hand of the 
manipulator. The strip may stick or be damaged. This undesirable 
manifestation of electricity is not derived from the paraffin but is the 
consequence of the fixation or hardening, especially with Muller’s fluid 
or by Deiter’s method. The presence of electricity was demonstrated 
by m,eans of the gold-leaf electroscope, which also showed that it is 
negative in quality. It is probably of frictional and not of chemical 
origin. The electrical phenomena are easily dissipated by the presence 
of moderate heat ; and prevented by exposing the piece to be sectioned 
to the air of the room for about half an hour previously. 
(4) Staining and Injecting. 
Study of Eye of Decapods.§ — Mr. G. H. Parker found that the 
rapid Golgi method, as described by Kolliker, yielded good results when 
applied to the optic organs of the Crayfish, especially when the prepara- 
tions, after having once passed through the silver bath, were again put 
into the solution of osmic acid and potassic bichromate, and then impreg- 
nated with silver. A third or even a fourth application of the silver 
solution often seemed advantageous. On the whole, better results were 
obtained from material imbedded in paraffin than from that in celloidin. 
In employing methylen-blue the author followed the general directions 
given by Retzius. The ganglia must be carefully removed and studied 
at once, as, soon after the death of the animal, the sharply differentiated 
blue stain begins to disappear. The author found that the methods of 
Retzius made it almost impossible to determine the precise location of a 
ganglionic cell, or the exact direction taken by its nerve-fibre. Since, 
however, these demonstrations were necessary, he attempted to devise a 
process for making sections from material stained in this way. In one, 
an account of which has already appeared, the tissues of the ganglion 
were fixed and the colour rendered permanent by means of watery cor- 
rosive .sublimate. The second, or newer method, essentially resembles 
the first, but the following steps are necessary in employing it. The 
ganglia, after being freed from the surrounding tissue, must be first put 
into an aqueous solution of sublimate, then successively into 30, 50, 70, 
and 95 per cent, of alcohol, each grade, of course, containing its proper 
proportion of sublimate. The material was allowed to remain in each of 
these fluids for about a quarter of an hour. From 95 per cent, alcohol it 
must be transferred for an hour to absolute alcohol containing 8 per cent, 
sublimate, then for another hour to a mixture of one part of this alcohol 
to one part xylol, and finally to pure xylol. In this last the preparation 
may stay indefinitely. Mr. Parker has found a great advantage from the 
* See this Journal, 1894, p. 403. f Tom. cit., p. 132. 
X Anat. Anzeig., xi. (1895) pp. 41-3. 
§ MT. Zool. Stat. Neapel, xii. (1895) pp. 3-7. 
