222 NORMAL HISTOLOGY. 



the sections are well washed in several waters, dehydrated 

 in alcohol, cleaned in oil of origanum, and mounted in 

 balsam. 



By this method the gray matter and connective-tissue 

 elements are stained yellowish brown, the nerve-cells 

 being stained of a darker color. The medullary sheath 

 of the nerve-fibres stains bluish-black to black ; the axis 

 cylinders remain colorless or are tinged yellow. 



Transverse sections from the cervical region of the 

 cord are stained by the acid fuchsin method of Dr. Ira 

 Van Geison as follows : 



Sections are stained deeply in hsematoxylin. They 

 are then washed well in water and stained for five 

 minutes in a mixture of acid fuchsin and picric acid. 

 This staining fluid is prepared as follows : To 100 c.c. 

 of a saturated aqueous solution of picric acid add a 

 saturated aqueous solution of acid fuchsin, drop by 

 drop, until the fluid becomes a dark-garnet color. After 

 staining, the sections are well washed in water, then in 

 two alcohols, cleared in oil of origanum, and mounted 

 in balsam. By this method, the nuclei are stained red- 

 dish purple ; the nerve-cells, axis cylinders, neuroglia, 

 and blood-vessels, are stained red ; the myelin, yellow. 



Sections of the Cortex of the Cerebrum and Cerebellum. 

 These are hardened in the same way as the spinal 

 cord. Sections cut perpendicular to the surface are 

 stained by the Weigert haematoxylin method and mounted 

 in balsam. Sections prepared by this method show the 

 course of the medulatted nerve fibres. For demonstrat- 

 ing the nerve-cells of the cortex, the sections are stained 

 with carmine or double and mounted in balsam. 



