338 PRACTICAL HISTOLOGY. [ xxx - 



downwards. The increase or decrease in the sectional area of some 

 other columns can only be made out by a study of degenerated or 

 developing cords. 



3. L.S. of Cord (Antero-posterior direction). Stain as for 

 T.S. (L and H.) 



(a.) Observe the longitudinally-arranged nerve-fibres in the white 

 matter of the anterior and posterior columns. In the anterior 

 cornu the rows of multipolar nerve-cells. 



(b.) The anterior roots passing obliquely through the anterior 

 column. 



(r,.) The posterior cornu, with its gelatinous substance and nerve- 

 fibres passing into and through it. 



4. Weigert's Hsematoxylin Method. 1 The myelin of medul- 

 lated fibres is stained of a deep blue-black tint, while degenerated 

 parts are not so stained; they are lighter just in proportion to 

 the disappearance of medullated fibres. The spinal co^d, or the 

 brain, is hardened for four to six weeks in Miiller's fluid, and the 

 hardened pieces are placed direct into 70 per cent, alcohol, and 

 must not be washed with water. Keep in the dark. Next day 

 add 90 per cent, alcohol, and harden completely in 95 per cent, or 

 absolute alcohol. Instead of Miiller's fluid, Erlicki's fluid may be 

 used. This is best done by keeping the fluid at the temperature 

 of the body in a warm chamber, when the hardening process is 

 completed in a few days ; but the results are not so satisfactory as 

 in the case of a cord hardened in the ordinary way. Small pieces 

 of the hardened tissue are placed in^a half-saturated solution of 

 neutral acetate of copper (i.e., a saturated solution is mixed with 

 its own volume of distilled water), where they remain for three to 

 five days. They are then transferred direct to 90 per cent, alcohol, 

 and can then be cut in alcohol, or the pieces can be embedded in 

 celloidin and then cut (p. 47). 



(A. ) The sections are placed for two or three hours in a few cc. of 

 Weigert's heematoxylin, in which they become black. 



Weigert's Hsematoxylin. 



Hrematoxylin . . . . . I pram. 



Alcohol absolute . . . . 10 cc. 



Cold saturated solution of lithium carbonate I ,, 



Distilled water . . . 90 



Dissolve the haematoxylin in the absolute alcohol, add the water 

 and boil. After it is cool, add the lithium carbonate. The time 

 which the sections remain in this fluid depends on what it is 



1 Fortschrit. d. Mcd., 1884 and 1885; Zeits. f. wissensch. MLTc., 1884 and 

 1885. 



