YAWNING AND SNEEZING 463 



been called, is effected by a jet, or whirlpool, of air set in 

 motion by the expulsatory action of the respiratory muscles 

 primarily, and by the oozing of cerebro-spinal fluid through 

 the Schneiderian mucosa, due to the opening of the glands 

 of Bowman secondarily. Thus, they are either blown away 

 or washed away. 



The new-born infant very early, or, in many cases, 

 immediately after breathing, gives evidence that the peri- 

 pheral nerves have become disturbed or affected through 

 the change of temperature of the medium by which it 

 is environed by an effort, or succession of efforts, at 

 sneezing. Thus, the changed circumstances of the child's 

 existence necessitate an easily available provision for the 

 regulation of intra-cranial and intra-spinal pressure the 

 equable temperature of its hitherto immediate surroundings 

 having been such that the cutaneous surface and other 

 convenient channels have been sufficient to afford the 

 required means whereas now the constantly changing 

 temperature of the surrounding air, into which it has been 

 born, is so " trying " for its peripheral nerve terminals 

 that a correspondingly increased provision of protective 

 mechanism has had to be secured to prevent disaster. 



The sigh may be called an echo of the stretch, and is often 

 attended by the proverbial relief. 



Weeping belongs to the same category of, more or less, 

 involuntary actions, and is only seen in human beings, 

 although in one or two instances it may be said to be 

 closely counterfeited, such as in the case of the proverbial 

 " crocodile's tears," and certain howls of the dog and its 

 congener the hyena. 



The whole of these natural movements, and combinations 

 of natural movements, seem to be the outcome of " natural 

 demands," and are the finished methods by which nature 

 effects needful changes in the static conditions of the fluids 

 of the body, and secures the equilibrium both of the 

 material and dynamic conditions of it generally, and of the 

 various organs and structures of it particularly. 



This exhaustive study, therefore, cannot fail in enabling 

 us to possess ourselves of a great natural means of meeting 

 natural systemic needs by natural systemic methods, in 

 natural systemic manner. 



