ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
551 
the cube. Upon the end of this arm is fixed the celloidin block, in 
which the object is located so as to lie parallel to one of the faces of the 
cube. A few slices are removed from the block, and then the latter is 
examined to ascertain the exact position of the object. This done, a mark 
is scratched on the cube face in the direction of the central line of 
the object. 
Owing to the direction of the arm, the object can] be cut in any of 
three planes, transverse, sagittal, or frontal, or even in a combination of 
two, e. g. half in one direction, the remaining half in another. 
Fig. 143. 
The idea of the apparatus is easily understood from the illustrations 
(figs. 140-145). 
Lignin Reaction of Wood.* — Herr F. Czapek has succeeded in find- 
ing a suitable method for obtaining lignin, the isolation of which has 
long been a desideratum. Wood sawdust is boiled for some minutes in 
chloride of tin solution, and the chromogenic substance extracted with 
benzol or ether. A cold saturated solution of sodium bisulphite acts in 
a similar way to the tin chloride. The amount obtained from 1 kilo, of 
wood is extremely small. The new body is called hadromal , and, accord- 
* Zeitschr. f. pliys. Chemie, xxvii. (1899) pp. 141-66. See Bot. Centralbl., 
lxxix. (1899) pp. 126-8. 
