428 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
- 
responding to stage 2, given above for mammalian development. Com- 
pare Fig. 15, which is the nerve cell of an 11mm. pig, with Fig. 5, which 
is the motor nerve cell of an adult Necturus, fixed in the same fluid and 
stained with the same dyes. Besides the staining reactions the effect of 
alkalies or of digestive fluids is practically the same in both cases. 
Levi" has examined the nerve cells of different types of Vertebrata 
( Vespertilio, Cavia, Cants, Bos, Testudo, Zamenis, Rana, Triton, Proteus, 
Spelerpes, Tinca, Raja, Scyllium, and Petromyzon), and has noticed the. 
peculiar nature of the nucleus in the cells of the Urodela. He offered 
no explanation of the peculiarities of these cells, nor did he draw any 
conclusion about the nature of the substance in the cytoplasm of other 
forms. 
A comparison of nerve cells of larval Asblystomata with those of the 
adult form shows them to be exactly similar. There is no transforma- 
tion, except to a slight degree, of the chromatin into an oxyphile and a 
basophile part. I have noticed that those cells of the adult that had a 
little basophile substance in the cell body also had some oxyphile 
substance in the nucleus. 
There are other forms that have not yet reached the adult or mam- 
malian degree of differentiation. Thus in Lzmax and Limne@a (and 
from the descriptions of Pflike and McClure, in all Gasteropods) the 
cells have stopped developing at a stage between 3 and 4 of the mam- 
malian development. There is a quantity of iron and phosphorus- 
holding substance in the body of the nerve cell, but the nuclear chro- 
matin is peculiar. It is not affected by digestive fluids, it stains green 
with the Ehrlich-Biondi stain, it stains with safranin, and is generally 
purplish with eosin and toluidin blue, although, by long action of eosin 
and short action of toluidin blue, it may be quite red. 
Other forms (earthworm and crayfish) were also noticed to vary 
slightly from the mammalian type. I believe that if the nerve cells of 
all adult animals were examined, one would find a complete series in 
the diffusion of the chromatic substance to the cytoplasm. 
8: Levi, G., ‘‘Su alcune particolarita di struttura del nucleo delle cellule nervose,’ Rivista di patho- 
logia nervosa e mentale, Vol. I, p. 141, 1896. 
Also: ‘‘ Ricerche citologiche comparate sulla cellula nervosa dei Vertebrati.’’ Ibid., Vol. II, pp. 193 and 
244, 1897. 
(Both papers inaccessible, quoted from the Zoologischer Jahresbericht for 1896 and 1897.) 
———— 
