374 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
frequently changed, for several days. To the alcohol, carbonate of lime 
may be added if necessary. When all the acid has been removed, the 
celloidin block may be sectioned. Now it may happen that, owing to 
extensive decalcification, there will be large gaps in the objects, which 
would be a source of considerable inconvenience in making and manipu- 
lating the sections. This difficulty is, however, easily got over by 
filling up the holes with 4 per cent, celloidin, and allowing this to set 
by evaporation. 
This method possesses many advantages ; there is no deformity of 
the animals or tissues, which are observed in situ , and it is easy and 
rapid. 
(3) Cutting-, including' Imbedding- and Microtomes. 
New Microtome (System Beck-Becker).* — Dr. Arno Beck describes 
an instrument which is intended to imitate the drawing and pressing 
motions of hand-cutting, and to improve on the pressing motion of most 
microtome knives. 
Fig. 61. 
Fig. 61 shows the principle of his knife. A parallelogram of metal 
rods is jointed at the four corners, and the back edge A B is clamped. 
D C represents the knife-edge, which, as it is moved forward, imitates the 
two motions desired. A uniform wear and tear of the knife-edge also 
results. Regulation of the lengths of the arms also regulates the thick- 
ness of the sections ; for the more elongated the curve described by the 
knife-edge, the finer the section. Adjustable screws through A and B 
determine the pitch of the knife. The guide arms A D and C B are 
strongly made, and are kept properly placed by strong springs with the 
intention of preventing the hopping of the knife. A small type of the 
machine successfully cuts sections of 5 by 7 to 6 by 8 cm. 
New Microtome by Reichert. t — Dr. J. Nowak, of Cracow, describes 
this instrument, which resembles the Fromme rocking microtome pre- 
* Zeitschr. f. wiss. Mikr., xiv. (1898) pp. 324-31 (5 figs.), 
f Tom. cit., pp. 317-24 (3 figs.). 
