1 8 Studies in Animal Behavior 



its feet about while in the shell. It pecks at food, 

 but before this it opens and shuts its mouth and swal- 

 lows some of the white. The ability of calves and 

 colts to walk soon after birth is attributed to their 

 struggles while still in the uterus. Even the human 

 foetus sucks in amniotic fluid and "learns to swallow 

 in the same manner as we learn all other animal ac- 

 tions which are attended with consciousness, by the 

 repeated efforts of our muscles under the control of 

 our sensations and volitions." 



Breathing, a more difficult case, is accounted for 

 as follows: "The inspiration of air into the lungs 

 is so totally different from that of swallowing a 

 fluid in which we are immersed, that it cannot be 

 acquired before our nativity. But at this time when 

 the circulation of the blood is no longer continued 

 through the placenta, that suffocating sensation which 

 we feel about the praecordia when we are in want of 

 fresh air, disagreeably affects the infant and all the 

 muscles of the body are excited into action to relieve 

 this oppression; those of the breast, ribs and dia- 

 phragm are found to answer this purpose; and thus 

 respiration is discovered; and it is continued through- 

 out our lives as long as oppression begins to occur." 

 Darwin is not daunted even by the clear indications 

 of instinct presented by social insects, for he says, 

 "If we were better acquainted with the histories of 

 those insects which are formed into societies, as the 

 bees, wasps and ants, I make no doubt but we should 

 find that their arts and improvements are not so 



