22 HEAD. 



T. It is possible that the regularity of the motion, 

 like that of musical sound?, may have a lulling effect, 

 and, so far as this cause is concerned, no injury per- 

 haps may arise. But you may be "aware, the prac- 

 tice is, after all, objectecrto by some medical writers. 

 They say, that sleeping should be purely natural in a 

 healthy infant, as it is in after life, and not induced 

 by the stupifying effects of any artificial means. 



You spoke of the skull as composed of several 

 bones. Is there any thing remarkable in the manner 

 in which they are united ? 



A. It is surprising, anatomists observe, to see how 

 the pieces are joined in the best possible mode for se- 

 curity. The edges, where the bones unite, are cut 

 into little teeth, in a sawlike manner, and interlock 

 closely with one another, so as to produce the firmest 

 joint. It resembles that strong mode of uniting which 

 is called the dovetail, or, more exactly, it is the fox- 

 tail joint of the carpenter, which he always employs 

 for strong work, when the pieces are small. Anato- 

 mists call it a suture. It makes the crinkling lines 

 which may be noticed on the outside of a dry skull. 



Fig. 1. 



one of the sutures on the outer portion of the skull. 



