NOTES ON THE TECHNIQUE OF WEIGERT’S METH- 
OD “FOR STAINING MEDULLATED:> NERVE- 
FIBERS. 
By OLIvER S. STRONG, 
Columbia University, New York. 
The following is not the outcome of a systematic investi- 
gation of the technique of the method of WeiGeErtT, but simply 
of experiments made at various times to secure the best results 
on material hardened as described below. Notes were often 
made which have been collated and the conclusions pre- 
sented, not so much as invariable improvements on the regular 
procedure, but as suggestions for securing better results in cer- 
tain cases. Inthe estimation of the success of a WEIGERT 
preparation, especial weight has been attached to the number 
of fibers revealed in the gray and the brilliancy with which they 
are demonstrated. 
The material consisted of portions of the central nervous 
system, especially the cord, of the human foetus, infant and 
adult. This.material was fixed in formalin, in potassium bichro- 
mate and formalin, or in copper bichromate. The fixation in 
formalin was usually accomplished by injecting into the blood 
vessels formalin I vol. + water several volumes. After re- 
moval the brain and cord were kept in formalin 1 vol. + 
water g vols. until used. Some material which yielded fine 
preparations had been thus kept in formalin for three years. 
The material fixed in potassium bichromate and formalin was 
usually fixed by an injection zz sztu of potassium bichromate 
5%, or stronger, several vols. + formalin 1 vol. After removal, 
the cord and portions of brain were further hardened in potas- 
sium bichromate 5 % g vols. + formalin 1 vol. about a week and 
in potassium bichromate 5% alone for ten days to 2 weeks or 
so. Finally, some material, the brain and cord of a 7 months 
