PLATE 9 



EXPLAXATION OF FIGURES 



In preparing these photomicrographs a Zeiss 1.5 mm. apochromatic objec- 

 tive and a 4 X compensating ocular were used. The magnification at the level 

 of the plate was about 1000 diameters. Seeds Process Plates were used. The 

 photographs were made with the aid of artificial illumination. The photo- 

 micrographs appear in reproduction at the original magnification. 



89, 92, 93 and 95 Fixed in Flemming's weak solution. 



90, 91, and 96 to 99 Killed in Flemming's strong solution. 



94 Illustrates the results obtained in poor fixation. This is a photograph 

 of a group of poorlv fixed spermatoeonial cells in the testes of a pig. 



218 



