662 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
plate can be drawn out from the frame. The sliding part g carries a 
metal arch d (11 by 9 cm. in aperture), and its movement is controlled 
by a rackwork b. The distance of d from f is regulated by a micro- 
meter c, and the screw a clamps g to li. When the slide has been set 
Fig. 164. 
at the desired thickness, the brain is pushed with the left hand through 
the arch d slightly pressed on the glass plate. The right hand grips 
the knife-handle and cuts through, leaning against the arch as a guide. 
The section usually adheres to the glass plate, which is then lifted out 
and immersed so that the section can be floated off. The author’s 
custom is to make preliminary slices 1*5 to 2 cm. thick, and, after 
immersion in Marchi solution, to examine them for signs of degenera- 
tion ; if any should be found, he cuts thin sections forwards or back- 
wards as required. He invariably keeps his sections in strict serial 
order, and if any be removed for examination a sheet of blotting paper 
is inserted to mark the gap. 
(40 Staining and Injecting. 
Hsematoxylin, Carmine, and allied Substances.* — Herr P. Mayer 
makes a useful and timely contribution on certain pigments used in 
microtechnique. Though limited to a consideration of logwood, haema- 
toxylin, haematein-cochineal, carminic acid, and carmine, the author’s 
compilation is an excellent summary and bibliography of what is known 
of these pigments. References are given to these stains and to their 
combinations. Though none of the descriptions contain anything new, 
the information conveyed in these short articles is extremely useful 
from historical, technical, and bibliographical points of view, and a 
perusal will repay those who are interested and occupied with staining 
sections and tissues. 
Flagella Staining.f — Prof. E. Zettnow records some recent improve- 
* Zeitschr. f. wiss. Mikr., xvi. (1899) pp. 196-220. 
+ Zeitschr. f. Hygiene u. Iufekts., xxx. (1899) pp. 95-106 (1 fig.). 
