MOVEMENTS OF THE ALIMENTARY CANAL 479 



in this connection that the colon is a smooth muscle structure, 

 under the control of the autonomic system, and subject, therefore, 

 to the disturbing influences characteristic of such structures. The 

 inclusion of ample roughage in the diet does not always suffice to 

 secure adequate evacuations, particularly where neglect or im- 

 proper treatment has affected the colon so that it no longer re- 

 sponds normally to mechanical stimulation from its contents. The 

 means commonly used to induce evacuations, the taking of purga- 

 tive drugs, is objectionable, although sometimes necessary, be- 

 cause the drugs act by irritating the intestinal lining. Such irrita- 

 tion, if repeated regularly, brings on a chronic inflammation, 

 which seriously impairs the ability of the colon to react normally. 

 The habit of taking purgative drugs should be strenuously avoided. 

 If persisted in it is sure to lead to much discomfort or even severe 

 suffering. It is probable that much of the trouble from intestinal 

 sluggishness could be avoided by proper supervision and care in 

 childhood, when regular habits are easy to establish' and enforce. 

 Regularity, even more than ample roughage, is a prime requisite 

 to the proper functioning of the colon. 



