PRACTICAL HISTOLOGY. 



[xvul. 



(a.) (H) Observe the large size of the cell (100 ^, ^Jo" inch, and 

 therefore visible to the naked eye), with numerous processes 

 branched processes which run in all directions (fig. 202). The 



processes branch ; and then 

 branch again and again to 

 form a fine protoplasmic 

 system of processes the 

 protoplasmic processes. 

 One process is always un- 

 branched, it is by no 

 means difficult to see the 

 axis-cylinder process 

 which becomes continuous 

 with, or in fact is, or be- 

 comes, the axis-cylinder of 

 a nerve-fibre (fig. 202, a). 



(b.) The multipolar cell 

 itself has no cell- wall, and 

 it contains a large, con- 

 spicuous, spherical, nucleo- 

 lated nucleus, the latter 

 with a distinct envelope. 

 The protoplasm is fibril- 

 lated, and the fibrils may 

 be seen to stretch into the 

 branched processes. Some- 

 times the cells contain pigment (fig. 202, I). 



10. Cover-Glass Preparation of multipolar Nerve-Cells. 

 (i.) From a perfectly fresh cord of a sheep or ox snip off a small piece 

 of the anterior cornu; press it between two cover-glasses, so as to form 

 a thin film. Separate the cover-glasses and allow the film adhering 

 to each to dry. Float the cover-glass film surface downwards 

 on a concentrated watery solution of methylene-blue for several 

 hours. Wash the cover-glass in water mixed with alcohol, drain it, 

 allow it to dry, and mount it in xylol balsam ; the cover-glass can 

 be passed through absolute alcohol, cleared with xylol, and mounted 

 in xylol balsam. The multipolar nerve-cells are all deeply stained 

 blue (T/tanko/er). 



(ii.) If the use of aniline colours be objected to, the following 

 method gives good results : For three or four days macerate a small 

 part of the grey matter of the anterior cornu in 20 cc. of water, 

 containing i gram of each of the following : Neutral ammonium 

 chroma te, potassic phosphate and sodic sulphate (Landois' fluid, 

 p. 26), and then stain it in bulk for 24-48 hours in equal parts of 

 the above solution and strong ammoniacal carmine. 



FIG. 202. A Multipolar Nerve-Cell from the An- 

 terior Coruu of the Grey Matter of the Human 

 Spinal Cord. a. Axis-cylinder process ; b. Pig- 

 ment, x 150. 



