1 82 The Ottawa Naturalist. 



eyes open, though it is likely they do distinguish between light 

 and darkness. 



It appears that all animals born blind are also born deaf; 

 at all events, 1 have as yet found no exception to this rule. 



The greatest difference sometimes exists as to the psychic 

 condition at birth of different groups of animals belonging to 

 the same larger group. This is well illustrated by the cavy 

 (Guinea pig) and the rabbit. The latter is born blind, deaf and 

 comparatively helpless, while the newly born cavy can in a few 

 hours run about, see, hear and even eat, yet both belong to the 

 great group of rodents or gnawers. This is to be explained by 

 the relatively short period of gestation of the rabbit, as compared 

 with the cavy, so that the young of the rabbit are born in a 

 comparatively immature condition. Even in the dog tribe there 

 are differences in rate of development for the different breeds ; 

 thus, small dogs, as terriers, are precocious as compared with 

 St. Bernards and other large breeds and they attain physical 

 and psychical maturity earlier. A terrier is generally quite 

 mature at one year, while a St. Bernard may grow and develop 

 for at least two years. 



The writer is not aware that a record of physical changes as 

 complete as the psychic has been kept in studies made on 

 infants. 



This omission he has in some measuYe endeavored to 

 to supply in his researches on the lower animals, because it is in 

 this way alone, probably, that the relations of the physical and 

 the psychic can be ectablished. So far as investigations have 

 been made they seem to show that psychic growth and develop- 

 ment run parallel with the development of the nervous centres, 

 especially the brain. 



The writer has completed a research bearing directly 

 directly on this subject, and the evidence is clear that the degree 

 of psychic development at birth and for some days after, in 



