278 JoURNAL OF COMPARATIVE NEUROLOGY. 
cH1! have reported the former, and Gorer*? and Levi® the 
latter. To determine what the value of the mitotic changes weie 
when pathologically induced, it was desirable to gather more 
details as to the changes in the nucleus during normal mitosis, 
and to this end the present investigation was undertaken. 
II. Materials used and technique employed for the present tn- 
vestigation. 
For the present investigation, foetal cats were exclusively 
used, the foetuses having body length (from the tip of the head 
to the origin of the tail) of 6.3 cm. At this stage of develop- 
ment they present abundant mitotic figures in almost every 
part of the encephalon, especially in the cerebellar cortex and 
the lining layer of the lateral ventricles of the hemispheres. 
Single sections of spinal cord of these cats showed rarely more 
than one or two dividing cells, and sometimes none were pres- 
ent. Five foetuses of the same litter were used for this inves- 
tigation. Asa preserving agent, Gitson’s fluid, CARNoy’s mix- 
ture, and Rrpart and Pertit’s fluid were employed in each case. 
The following is a formula recommended by Ripart and Petir:* 
Camphor water (dilute) : > 75 grams. 
Distilled water : - : 75 grams. 
Crystalized acetic acid . : I gram. 
Acetate of Copper é : : 0.30 gram, 
Chloride of Copper. ‘ 0.39 gram. 
(Osmic acid may be added to the fluid of RIPART and PETIT to increase 
the fixing power.) 
In each case the fluid was used according to the direction 
' TepESCHI: Anatomisch-pathologische und experimentelle Untersuch- 
ungen tiber die Regeneration des Nervengewebes. Vor. Mitth. Centra/él. /. 
Allg. Path. u. path. Anat., Bd. VIII (’96) ; also Anatomische-experimentelle 
Beitrage zum Studien der Regeneration des Gewebes des Centralnervensystems. 
Beitr. 2. path. Anat. u. 2. Allg. Path. ’97, XXI1. 
2 GoLcl: Berliner Klin. Wochenschr. ’94, p. 325. 
8 Levi: Ricerche sulla capacita proliferativa della cellula nervosa. ev. 
di patol. Nerv. e Ment., ’96, f, 10; also Sulla cariocinesi delle cellule nervose. 
Rev. di patol. nerv. e ment., 98, f. 3. 
* This formula is given in LEE’s Microtomist’s Vade Mecum. 
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