120 NAOKI SUGITA 
Formaldehyde fixation and paraffine imbedding (2A) causes 
considerable shrunkage of nuclei and cell bodies, especially in 
young brains, but material so prepared takes any aniline dye ex- 
cellently well (fig. 1, 6). Fixation in Miller’s or Orth’s fluid and 
paraffine imbedding (4A) eauses also shrinkage and deformation 
of the cell bodies and nuclei, the contours of which become zigzag. 
Formaldehyde fixation and celloidin imbedding (2B) give good 
figures of cell bodies, which stain excellently with any aniline 
dye. The shrinkage of cells and nuclei which was seen after 
paraffine imbedding of the material similarly fixed (2A) is no 
longer observed. But the size of cell bodies and nuclei seems to 
have suffered some diminution. Miller or Orth fixation and 
celloidin imbedding (4B) causes considerable deformation of the 
contours of the cells and nuclei, which is probably an affect of the 
potassium bichromate. 
In material fixed in 95 per cent alcohol, the brain is subject to 
much shrinkage, and consequently the cell size and cortical 
thickness diminish also, though, after paraffine imbedding (3A), 
the contours of cells and nuclei are preserved pretty well (fig. 1,° 
a). Aleohol fixation only or alcohol fixation and celloidin im- 
bedding (3B) is ideal for the study of the cytoplasmic structure as 
originally emphasized by Nissl. The cell bodies stain very well 
with aniline dyes, but the section shrinks so that the individual 
cells must have been more or less reduced in size. Fixation in 
Ohlmacher’s fluid and paraffine imbedding (5A) or celloidin im- 
bedding (5B) proved to be most excellent for cell study, as 
pointed out by King (10), but it is followed after fixation by a 
considerable reduction in the volume of the total brain and some 
change in shape. 
After a number of tests, I decided to use as the fixative Bouin’s 
fluid, which is composed of: 
Picrieracid-esaturabedsagueousisOlmblone ath eenanr sete neers 75 
40pericent formaldehyde (formalin). eee cmeeel ke bioeeeneecee 25 
Glacialvacetiesacidis sae lt tthe, 3. ces tue Se ote ad Oe leet ee Tae eG 5 
Fixed in this fluid the total weight or volume of the brain 
suffers no significant change after complete fixation and preserves 
its original shape quite well, though a slight shrinkage occurs, 
