THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS) 263 
hear, taste, pick up and swallow food, drink, run about, 
etc. 
Its progress is so rapid that in a few days it can lead 
an independent existence, provided it be protected 
against cold, wet, etc. 
The chick stands to the pigeon in physical and 
psychic development, in somewhat the same relation as 
the rabbit to the cavy or guinea-pig. 
In all these cases, when full maturity is reached, the 
psychic difference is not great. The rabbit and the 
cavy are about on the same mental plane, and so are 
the pigeon and the fowl. 
They all illustrate general laws of development, and 
the study of these creatures, somewhat low in the 
vertebrate and psychic scale, seems to me to throw 
much light on the problems of psychology, viewed not 
as human psychology alone, but in the broadest possible 
sense, 
