(e) Cells Showing- Nucleus and Accessory Nucle- 

 us (Nebenkern). 



Small pieces of a guinea pig's testis were hardened in the 

 folldwiiii: iiiixt lire : 



Osmic acid, 2% solution 2 parts, 



riatinnin chloride, 2% solution 3 " 



^lercuiii- chldride, saturated aqueous sol. 5 " 



They are hardened for 24 hours. enil)edded in paraflin, sectioned 

 and llxed to cover glasses, stained in iron-lack-hiiematoxylin 

 (Ilaidenhain's), dehydrated, cleared in oil of berganiot, and passed 

 into xylol. Come to the talde with a small drop of l)alsam on your 

 slide. 



Search fortitl)ules showing- the last stages of tlie devel- 

 opment of the spermatozoa. In the cells forming the walls 

 of tlie seminiferous tubules, the accessor}'- nucleus is stained 

 deeply black, the nucleus a bluish-gray color. Sketch 

 several of the cells showino; this structure. 



'a 



DRAWINGS FOR LESSON I. 



