122 



THE GROWTH OF THE BRAIN. 



and the weight of the body in several species of dogs is 

 here quoted from Wilder. 1 



TABLE 23. THE WEIGHT OF THE BRAIN AND OF THE BODY, 

 AND THE RATIO OF THE TWO, IN DOGS OF DIFFERENT 

 SIZES. (Wilder.} 



There are two factors at work to bring about the 

 different ratios here given. In the first place, the brain 

 at birth has more nearly completed its growth than has 

 the body ; young dogs, like the first two mentioned, 

 have, in common with all other young vertebrates, the 

 brain disproportionately large ; and in the second place, 

 the large varieties grow for a longer time. Cases 3 

 and 4 in this table may be cited, as showing the 

 difficulty of making a correlation between brain-weight 

 and intelligence. The large English terrier, 3-5 years 

 old, has approximately only one-seventh of the body- 

 weight, and but one-half of the brain-weight, of the 

 Newfoundland. The ratios are correspondingly unlike, 

 yet certainly both of them belong to the breeds counted 

 as intelligent, and it should be safe to say that the 

 difference between the respective ratios of their brain 

 and body-weights is out of all proportion to the pre- 

 sumptive difference in their mental powers. 



1 Wilder, Rep. Aw. Assoc. Advancement of Science, 1873. 



