122 



PHYSIOLOGY FOR THE LABORATORY. 



lines. In one draw parallel horizontal lines, and in the 

 other parallel vertiqal lines. How do the two squares 



FIG. 15. 



now compare in size and shape? Which would make a 

 person look taller, vertical or horizontal lines? 



c. Look at the rows of letters, *, and the figures, 8. 



s s s s s s s 



8888888 



FIG. 16. 



Do the upper and the lower halves appear to be of the 

 same size ? Invert the page and look again. 



d. ZOLLNER'S LINES. Make six parallel vertical lines. 

 Do they appear parallel? Draw short parallel oblique 

 lines across them, so that those on adjacent verticals 



FIG. 17. 



