Journal of Applied Microscopy. 



613 



and marked with lines to show the exact position for the sections. It is a 

 good plan to number the rows of sections on strips of paper gummed to the 

 slide and to the cover (Fig. 3). This will show any error in the mounting of the 

 series, and the strips of paper protect the glass which may be easily broken 

 after one has worked several months on the series. E. M. Brace. 



Noack, Wilbelm, Eine Methode zur Orienti- 

 ning kleiner Objecte beim Zerlegen in 

 Schnitte. Zeits. f. wiss. Mikr. 15 : 438-443, 

 i8qq. 



With this method small objects may be 

 accurately oriented by the use of the 

 microscope, and both cross and longi- 

 tudinal sections may be made from the 

 same specimen. A metallic cube measuring 16 mm. on each edge has a bar with 

 rough upper surface for the parafifin block, fitted on diagonally at one corner (Fig. 1). 

 A line drawn on one side of the cube serves to mark that surface in different posi- 



tions. The paraffin block may be cut in three different planes, making cross, 

 frontal and sagittal sections — as may be seen by turning the marked surface of 

 the cube about (Figs. 1, 2, 3). The cube, czrry'mg the paraffin block is 

 clamped in position in the microtome, and a line made on it along the edge of 

 the plate that holds it in place so that the cube can be removed and brought 

 back to the same position again. A trial section is now cut, and placed under 

 the microscope and the cube with the paraffin block placed close to the side of the 



FIG. 4. 



microscope, in a corresponding position. By looking through the microscope at 

 the section with one eye, and at the cube with the other, the dorso-ventral plane 

 of the object may be determined, and a line drawn on the cube to indicate the 

 direction in which it lies. (Fig. 4.) The fact that the microscopical image is 



