588 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
in the median plane, and sometimes also one in the same plane on the 
outline of the surface of some central organ. 
The photo or sketch is then enlarged on a sheet of Bristol board, to 
correspond with the magnification of the sections and the enlarged figure. 
If only an enlarged model of the entire embryo is desired, it is merely 
necessary to arrange the wax sections within the Bristol board outline, 
and then smooth off the outer surface with a warm modelling tool. If, 
however, it be desired to reconstruct an internal organ, the process is more 
complicated, for then the second guiding-point (that on the surface of 
some central organ) is necessary. “ In cutting out of the wax plates 
the outlines of the sections of the organ to be reconstructed, this point, 
along with that on the dorsal surface, is cut out so as each to form a 
point of the piece of wax that remains connected with the sections of the 
organs by bridges of wax.” When the series of wax sections has been 
cut out, they are arranged in their proper places on the Bristol board, 
care being taken that the two guide-points fall within the plane of the 
Bristol board, and that the line passing through them is perpendicular 
to the dorsal line. When all are in place, all that remains is to smooth 
off the outer surface of the model. 
Method of preparing Rotifers.* — M. N. de Zograf has used a modi- 
fication of Rousselet’s earlier method for narcotising Rotifers with cocain, 
and staining with osmic acid. The animals are first treated with an 
aqueous solution of hydrochlorate of cocain, which is added drop by drop 
to the specimen fluid. The methyl-alcohol used by Eousselet is con- 
tinued. As soon as the animals begin to draw in their antennae, a few 
cubic centimetres of dilute osmic acid are added, and in from 2-4 minutes 
mixed with 10 per cent, wood-vinegar (pyroligneous acid). The fluids 
are slowly poured off and replaced by alcohol. The animals do not lose 
bulk, and may be preserved in glycerin or mounted in balsam. 
Demonstrating presence of Flagella of the Plague Bacillus.^ — 
Mr. M. Gordon, working under the direction of Dr. E. Klein, began with 
a gelatin culture of the plague bacillus. From this a bouillon culture 
was made and incubated at 37°, and small doses thereof were injected 
subcutaneously into a guinea-pig. The animal died in two days, and 
characteristic organisms were found in the lymphatic glands and spleen. 
Plate cultivations were made from the heart-blood, and typical colonies 
reinoculated on oblique agar. After 20 hours 5 incubation at 37°, cover- 
glass preparations were stained by van Ermengem’s method. In suc- 
cessful preparations rodlets are found which possess at one end a spiral 
flagellum about double the length of the organism. Occasionally a second 
spiral flagellum at the same end, but attached laterally, is present. The 
flagella are only stained with difficulty, apparently owing to the presence 
of some viscid substance by which the organisms are invested. Slight 
movements are visible in hanging drop preparations of agar cultures. 
Decalcifying and Desilicating Sponges.J — Dr. E. Rousseau de- 
calcifies sponges which contain much lime salt, such as Leuconia, Leu- 
candra , Leucosolenia , Sycon, &e., by first hardening pieces the sides of 
which are not longer than 2 cm., and then imbedding in celloidin. 
* Comptes Rendus, cxxiv. (1897) p. 285. See Zeitschr. f. angew. Mikr., iii. 
(1897) p. 116. f Centralbl. Bakt. u. Par., l te Abt., xxii. (1897) p. 170. 
J Zeitschr. f. wiss. Mikr., xiv. (1897) pp. 205-9. 
