The Wealth of Nations by Part 1 Chapter 7 Page 24

for many centuries, but in the other it can last no longer than the lives of some of the workmen who were bred to the business in the time of its prosperity. When they are gone, the number of those who are afterwards educated to the trade will naturally suit itself to the effectual demand. The police must be as violent as that of Indostan or ancient Egypt (where every man was bound by a principle of religion to follow the occupation of his father, and was supposed to commit the most horrid sacrilege if he changed it for another), which can in any particular employment, and for several generations together, sink either the wages of labour or the profits of stock below their natural rate.

This is all that I think necessary to be observed at present concerning the deviations, whether occasional or permanent, of the