32 



STUDIES ON PATHOLOGIC OVA. 



Fio. 3. Method of piling with cardboard outline as guide: 1, external form piled in wax plates; S, cardboard outline 



guide; 3, posts for attaching same; 4, baseboard. 



Lewis (1915) and is known as the Lewis guide liner (fig. 4). After the guide-lines 

 have been drawn on each wax plate they are transferred to the photographs 

 or drawings. This is done by superposing each wax plate upon its photo- 

 graph or drawing and marking 

 the end of the guide-lines. When 

 the wax plate is removed, these 

 points are connected by lines 

 similar to those on the plates. 

 After the two principal guide-lines 

 have been established, it has been 

 found convenient to use secondary 

 guide-lines, 5 cm. apart, which run 

 parallel to the primary ones over 



the entire Surface Of the photO- Fio. 4. Method of making guide lines: 1, baseboard; 2, perpen- 

 OTflnh dicular posts; 3, straight edge; 4, piece at right angles to it. 



In order to make a reconstruction of any portion of an embryo it is necessary 

 first to transfer the outlines of that structure from the photograph to the wax 

 plates by means of carbon paper and a glass point used as a pencil. These outlines 

 are then cut and removed from the wax and the plates squared off along the 



