INFLUENCE OF HABIT. 285 



If, again, the change be from a healthy situation 

 to one only a little less favourable, the consequences 

 to the system will be also gradual and progressive. 

 No immediate injury to health may be apparent, 

 and the body may be said to adapt itself to the cir- 

 cumstances, but, in reality, health will be lowered in 

 tone, and life shortened, in exact proportion to the 

 amount of the injurious exposure, and the state of 

 the system at the time. Individuals of a peculiar 

 constitution may live long, but the average of health 

 and life will be positively lowered, a fact which 

 shows that the apparent exception is more a fallacy 

 than a reality, and that, c&teris paribus, the highest 

 health and greatest vigour will always be on the side of 

 those who make the nearest approach to the fulfilment of 

 the organic laws. 



It is, therefore, a glaring perversion of logic and 

 reason to infer that we may safely rest satisfied 

 with a limited portion of evil, on the plea that the 

 constitution will adapt itself to its presence. The 

 argument ought to be turned in exactly the opposite 

 direction. If the constitution possesses this power 

 of adaptation to the extent supposed, it becomes 

 doubly incumbent on us to have it always surrounded 

 with beneficial influences, seeing that, when the laws 

 of health shall be fulfilled, the same tendency to 

 adaptation will then operate with equal force in 

 permanently ameliorating the constitution. In 

 every point of view it is, therefore, an object of 

 much consequence to us to become acquainted 

 with and to obey all the laws which regulate the 

 functions of the human body. 



It would be easy, were it consistent with the 

 limits and purpose of the present volume, to show 

 that although great advances have been made of 

 late years, both in physiological knowledge and in 

 its applications to the advancement of human hap- 

 piness, many of the usages current in society, and 

 many of the practices resorted to in education, are 



