i io PRACTICAL HISTOLOGY. 



179. Suprarenal Body (L. and H.) Examine V. S. 

 suprarenal body prepared as follows : Harden in Miiller's 

 fluid for a month, and then in methylated spirit for a fort- 

 night. Mount the sections in glycerine or dammar. Groups 

 of nucleated brownish cells are seen with (H.) They are 

 chiefly placed in the outer part of the organ, arranged in 

 rows, or in irregular clusters, in spaces amidst the fibrous 

 tissue. 



LUNG. 



A section of the trachea has already been examined 



( "5). 



1 80. Methods. a. The lung may be extremely well 

 prepared by hardening in chromic acid, and then in alcohol, 

 as directed in 6. 



b. The outlines of the epithelial cells in the alveoli may be silvered 

 as follows : Allow the lungs to collapse by opening the chest of an 

 animal just killed. Inject a half per cent solution of silver nitrate into 

 a bronchus, and fully distend the lung. Make sections at once in the 

 freezing microtome, using distilled water instead of the gum. Wash 

 the sections in distilled water, and expose them to the light in it. 

 Preserve in Farrants' solution, or in glycerine. Some sections may be 

 good, but the staining is apt to fail. 



c. Sections of lung, either fresh or hardened in chromic 

 acid and spirit, are best made with the freezing microtome. 

 The spirit must of course be previously removed by im- 

 mersing the piece of lung in water for twelve hours or so. 

 Good sections may, however, also be made without a 

 machine, by imbedding the lung in gum, as described in 

 301, b. The gum is easily removed from the sections by 

 placing them in water. 



d. The sections may be examined unstained or stained 

 with logwood. If unstained, they are mounted in Farrants' 

 solution or glycerine ; if stained, they may be preserved in 

 the same fluids, or in dammar ( 152). 



e. The blood-vessels of the lung may be injected, e.g. with carmine 

 and gelatine ( 343). The lung is then hardened in alcohol, as de- 

 scribed in 337, and sections made as above mentioned. 



f. The ganglia of the lung may be examined in sections of the 

 lung, hardened in chromic acid in the usual way. They are found 



