P RE FA CE. 



I HAVE written this book to show that the Law of Life for man 

 is written in his organisation ; that we have but to study the 

 physical nature of man to know the conditions of health, the 

 causes of disease, the means of preventing diseases, and the 

 best methods of cure ; that, in the same way, we have but to 

 understand his moral nature, his social requirements, and the 

 constitution of his mind, in order that we may know the moral, 

 social, and educational conditions most conducive to his wel- 

 fare and happiness. That is, I have endeavoured to prove the 

 proposition laid down in my title that Human Physiology is 

 the true basis of Sanitary and Social Science. 



But why, it may be asked, is it necessary to write a volume 

 of nearly five hundred pages to demonstrate and illustrate a 

 self-evident proposition? Of course, the law of every creature's 

 life is written in its organisation. It is true of every plant, 

 every animal, and must therefore be true oi man. We have 

 only to understand his whole nature to see its adaptations, and 

 the modes of life and activity, the manners and morals, govern- 

 ment and society, education and religion, that will best suit his 

 requirements. 



But it has seemed to me that the great difficulty is that men 

 have little knowledge of their own natures. Men understand 

 but little of their physical constitutions/ not much more of their 

 mental and moral characters. Physiology, the science of life, 

 has been handed over to the medical profession, which has an 

 unfortunate interest in the popular ignorance of sanitary laws \ 



