550 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
shown in section in fig. 139, the sphere works between two plates, of 
which the lower is in position for Zeiss’ p reparation Microscope, and 
the upper can be so pressed by a screw against the lower that the 
sphere becomes firmly fixed. A rectangular frame, whose walls are per- 
pendicular to one^another and to the horizon, is then applied. 
The sphere is first smeared with a thin resinous layer and allowed 
to dry ; the object, soaked in cedar-wood oil, is then applied, and se- 
cured with collodion. The orientation is now accomplished by aid of 
the Microscope, the sphere secured, the frame applied, and the paraffin 
poured in. If the sudden warming is objectionable, pieces of solid 
paraffin are inserted, and the whole is placed in the thermostat. After 
cooling, the block with the object is easily lifted off. In cases where it 
would be disadvantageous for the object to lie so close to the outside of 
the paraffin block, it is well to lay between the sphere and the object a 
bit of a larger embryo or some similar material saturated with paraffin 
and easy to cut. 
Dr. Jordan states that he has obtained good results both in orienta- 
tion and in sections (serial or single). He worked with embryos of 1 
to 3 mm. 
Fig. 140. 
Fig. 141. 
Fig. 142. 
Method for Orienting Small Objects.* — Herr W. Noack describes 
the method used by him for orienting small objects in sectioning. A 
metal cube, the faces of which are 16 mm. long, is provided with an 
arm projecting from one angle in the direction of the diagonal of 
* Zeitschr. f. wiss. Mikr., xv. (1899) pp. 438-43 (6 figs.). 
