no 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tlien soaked in cedar oil. They are next soaked in paraffin for 20 minutes. 
The series of sections are stuck on the slide with castor-oil collodion, and 
after the removal of the paraffin with xylol, mounted in balsam. 
For studying the division of the nuclei in the Malpighian vessels 
of Dytiscus marginalise the author used Kleinenberg’s picrosulphuric 
acid for hardening. This was found specially advantageous in that it 
decolorized the dark-brown granules which beset the cell-plasma. 
By staining with borax-carmine and then treating with acidulated 
alcohol, a beautiful colour was obtained. 
Preservation of Mucous Granules in Secretory Cells.* — Mr. J. N. 
Langley advises the following method for preserving mucous granules 
in secretory cells. The animal is killed by bleeding or decapitation. A 
small piece is then snipped off a salivary gland, the piece having been 
previously pierced with a threaded needle. The piece of gland is sus- 
pended by the thread in a bottle, which contains some 2 per cent, osmic 
acid. The thread is fixed between the stopper and neck of bottle, and 
the piece of gland hangs just above the level of the fluid. The object 
is hardened in about 24 hours. It is then removed, washed for a few 
minutes in water, and then for 15 minutes apiece in 30 per cent, and 
50 per cent, spirit. Next, for half an hour apiece in 75 and 95 per cent, 
alcohol ; finally for one or two hours in absolute alcohol. The prepara- 
tion is then soaked for half to one hour in benzol previously to being 
imbedded in hard paraffin. The series of sections are fixed on the slide 
with albumen stained with methylen-blue, and mounted in balsam. Or 
the paraffin may be dissolved out by means of benzol or turpentine. 
This method is said to give good results with mucous cells from the 
mucosa of many of the lower vertebrata. 
Removing the Jelly and Shell from Frogs’ Eggs.j — The method 
for removing the coverings from frogs’ eggs recommended by Prof. F. 
Blochmann is essentially the same as that previously advocated by 
Prof. C. 0. Whitman. 
The author employs eau de Javelle, a solution of hypochlorite of 
potash, while Whitman used sodium hypochlorite. The ova which have 
been jweserved in chrom-osmium aeetic acid, and been well washed in 
water, are placed in the solution, twice or thriee diluted, and then 
shaken up by inverting the vessel. The eggs, freed from their gelatiuoid 
coat, sink to the bottom in 15 to 30 minutes. They are then very 
carefully washed in water, and afterwards transferred to strong spirit. 
If the eggs be kept in the dark the chromic acid is removed more 
effectually. The author recommends borax-carmine for staining. Hsema- 
toxylin is not suitable. 
Carbonate of Ammonia for demonstrating Sarcolemma.J — Prof. B. 
Solger recommends a cold saturated solution of ammonia carbonate for 
demonstrating the sarcolemma of frog’s muscle. In this solution the 
musele is placed for 3 to 5 minutes, and having been teased out, examined 
under the Microscope. The reaction is more complete if the animal be 
previously kept for several weeks in captivity. 
* Journal Physiol., x. (1889) pp. v. and vi. 
t Zoo\. Anzeig., xii. (1889) p. 269. 
X Zeitsclir. f. Wiss. Mikr., vi. (1889) p. 189. 
