SYMPATHETIC CELLS: NORWAY RAT 335 
cates in the Norway an increase during this same interval, which 
is about 135-fold, or nearly ten times as large. One circumstance 
which contributes to this result is the lower standard which was 
taken for the large cells in the Norway, in order to get a reason- 
able number of such cells at birth. The use of this lower standard 
gives of course a higher number at maturity in the Norway. 
This is, however, a trifling matter, and the more important dif- 
ference between the two strains lies in the relatively smallnumber 
of large cells in the Norway at one day of age. 
This is an expression of retardation in the early growth of 
the Norway in captivity—a peculiarity which has been noted 
by several observers and which has been demonstrated by Dr. 
Helen D. King for the general body growth. . 
Here again it is not possible to offer a precise explanation, 
for this relative retardation may be a character of the Norway 
in the wild state and hence difficult to study, or it may be a 
response to captivity, as these observations were made on young 
born in captivity from Norways not yet domesticated. 
It is possible, however, to conclude that the retardation in 
the early development of these cells is found in the wild as con- 
.trasted with the domesticated standard strain. 
To determine the general significance of these results, a brief 
review of some earlier observations along similar lines may be 
of value. 
In the presentation of these the data for the wild Norway 
will be taken as the standard, as this is the strain from which 
the Albino has been derived. 
As compared with wild Norways of like body weights, the 
standard Albinos have lighter brains and lighter spinal cords 
(16 and 12 per cent, respectively; Donaldson and Hatai, ’11). 
Further, two portions of the brain, the olfactory bulbs and the 
paraflocculi, are, relatively, still lighter in the Albino. 
As between the sexes within the same strain, it was found that 
while the weight of the spinal cord (on body weight) was similar 
in the two sexes in the Norways, yet in the standard Albinos 
the weight of the cord in the female was relatively heavier than 
in the male (Donaldson and Hatai, ’11). 
