ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
261 
Staining is advantageously effected by Ranvier’s picrocarmine. To 
study the mode of termination of tlio nerves in tbo ommatidium the 
author recommends a process which consists in forming within tho 
nervous elements a coppery layer of haematoxylin. On removal from 
the alcohol the depigmented piece is put for twelve hours into a solution 
of 1 per cent, sulphate of copper. This is then washed for five or six 
hours in distilled water, which is frequently renewed. It is then im- 
mersed in a solution which is not prepared till the moment of using it ; 
this consists of 75 ccm. of perfectly distilled water, 25 ccm. of absolute 
alcohol, and 0*25 grm. of crystallized haematoxylin. After immersion 
for twelve hours the piece is withdrawn, care being taken to avoid the 
use of any metallic instrument, and it is put at once into a 1 per cent, 
solution of sulphate of copper ; after twelve hours it gives its proper 
tint. The piece is then washed very carefully for several hours so as to 
get completely rid of the copper, and it is then dehydrated in baths of 
alcohol of increasing strength, always kept neutral. The piece is then 
treated successively with chloroform and paraffin. Sections fixed by 
the aid of albuminous water are mounted in dried Canada balsam, dis- 
solved in chloroform. Tissues treated in this way have a splendid deep 
Prussian blue colour, which is almost exclusively confined to the 
cylinder-axes, the protoplasm, and the nuclei of the nerve-cells ; the 
connective tissue takes such a slight tinge that one can scarcely recog- 
nize the nuclei. Unfortunately preparations thus obtained do not last 
long, even if kept in darkness. 
Examination of Sub-cuticular Layer of Ascarids.* — M. Jammes 
has been able to make some interesting observations on fresh specimens 
of Ascaris without any other preparation than staining in a watery 
solution of methylene-green. The best way to fix the cells is to hold a 
living worm between two pairs of scissors pretty close together, and to 
plunge the scissors and the piece of the worm between them into a 
solution of osmic acid, and then with both hands at once to cut through 
the specimen. Teasing may be effected in a solution containing one- 
third of alcohol. Besides methylene-green, borax-carmine, acid carmine, 
Delafield’s haematoxylin, and others may be used. It is often well to 
use more than one reagent. On the whole, haematoxylin gives the most 
marked and permanent results. Chloride of gold was also found to be 
useful. 
Method of obtaining Embryos of Balanoglossus.f — Mr. T. H. 
Morgan finds that Bateson’s method, somewhat modified, is the most 
satisfactory means for obtaining embryos of Balanoglossus. Collect tho 
sand around the adults carefully, and allow it to settle in tall glasses 
filled with water ; keep the water in rapid rotatory motion. Siphon off 
sand and debris. If the young are required in a living state they can be 
picked out with a pipette. The embryos can be collected much more 
rapidly by pouring Kleinenberg’s picrosulphuric acid, mixed with glacial 
acetic acid, in 2 to 10 parts per cent, of the whole solution over the 
sand collected through the siphon. The embryos are quickly coloured 
dark yellow, and so may be easily and rapidly collected. 
* Ann. Sci. Nat., xiii. (1892) pp. 325-7. 
f Zonl. Anzeig., xv. (1892) p. 457. 
