PRACTICAL INSTRUCTIONS. 



467 



Paraffin sections ready cub and stained may easily be 

 mounted by the following procedure : Place a clean slide on 

 a white sheet of paper. Draw a pencil outline and then a 

 line | inch from one end across the outline to allow for the 

 label. Make a mixture of distilled water and Mayer's albumen 

 (v. Appendix) in the proportion of 10 c.c. water to 1 drop of 

 albumen, and cover the part of the slide on which you wish to mount 



Fig. 76; The Hen's Egg at the time of laying x 



BA, blastoderm. SH, 

 white or albumen. WC> 

 vitelline membrane. 



egg shell. SM, shell membrane. SV, air chamber. WA. 

 chalaza, or twisted cord of denser albumen. Y, yolk. Z, 



the sections with some of the mixture. Upon this float the sections 

 in the desired order, and warm over a flame or on the paraffin 

 oven until the sections are flattened out. Care must be taken not 

 to melt the paraffin. Then run off the water. Arrange the 

 sections neatly in order, and leave them till perfectly dry. When 

 dry, the paraffin can be dissolved out with xylol, and the sections 

 stained and mounted. 



Wash in absolute alcohol and mount in balsam. 



