BRAINS OF EUROPEAN AND AMERICAN RATS COMPARED 85 
TABLE 14 
Mus norvegicus, Paris. Weight of brain and spinal cord 
NUMBER OF CASES BY | ; Se oe hae 
wetous nour |____ nee eee eee) UTE 
M. F. Brain | Spinal cord 
a i | grams mm. grams | grams 
HELE BOONES Af ae 1 ate 1686 Piet, (1/2) 1410 0804s 
PAOINAPAS( U2 Siete heer citer 3 il EY atl 219 2.2028 | 0.6838 
PAS} 0, Ue Ree eee eee eee 1 0 293 .0 230 2.3514 | 0.8630* 
BOI SOU sae ceeras Oee tere 2 0 317.0 227 2.2133 | 0.7785 
TABLE 15 
Mus norvegicus, London. Weight of brain and spinal cord 
NUMBER OF CASES BY 
andan Clea ces Bone Cheon |e lids as saan 
M. F. Brain Spinal cord 
Pz grams mm. | grams | grams 
POY os ts ese, Be va ae 173.0 197 2.0959 0.5815 
PADIS). ee tacee Seen | 1 3 208.5 210 | 2.1404 | 0.6328 
OM ck soca ate os | | | 
UO DU ane Se) 6 es ound Sd nce | 1 0 305.0 237 | 2.2440 | 0.8031 
*As this record for the spinal cord, which is correct, is also exceptional and is 
based on a single case only, the record is not used in computing the percentage 
deviations given in table 16. 
TABLE 16 
Mus norvegicus. Mean percentage deviation of the weight of brain and spinal cord 
in the Paris and London series from the standard values for the Philadelphia 
Norways 
A. Comparison on the basis of body weight, as given in table 2 
MEAN PERCENTAGE DEVIATION 
| 
SERIES — ta — 
| Brain Spinal cord 
PPA Skee ee a ies Seen ae A | +2.0 +2.7 
[Loi 6rd <A ene Pls ee EE | 0.0 +1.4 
UGTA RO SE ROTOR eke | +1.0 +2.0 
B. Comparison on the basis of body length 
PAE S ase gE NS hes sos ay oo vse ohiad in Po eR +2.9 | +4.5 
LOIN Git; Stee Aha ee nm a La le —0'2 | +0.9 
PATER A aD N ee B) . 8 1S Seige SOOM Se | | a! | Sei 
Average Ol. bOun Aw andsbasye ads aceee ae +1.2 | +2.4 
