Machinery has made it possible to produce more and more food in vast

areas, such as the plains of America and Russia. Crops have increased

almost everywhere and people are growing more and more food. 46. New

forms of preservation have also been developed so that food need not be

eaten as soon as it has grown.

Progress in medicine and hygiene has made it possible for people to

live longer. People in Europe and North America live, on the average,

twice as long as they did a hundred years ago. In other countries, too,

people generally live much longer than they once did. Babies,

especially, have a far better chance of growing up because of increased

protection against infant disease. 47. However, all countries do not

benefit to the same degree from this program in medicine and hygiene.

In prehistoric time, people from Africa and Asia migrated to other

continents. Europe was occupied by people from the East, America by

groups from Asia. During the nineteenth and twentieth centuries,

migrations have taken place within certain countries: the cities with

their industries have attracted people away from the country. 48. The

possibility of earning a fixed salary in a factory or office was more

attractive than the possibility of staying on the farm and having one’

s work destroyed by frost, storms, or droughts. Furthermore, the

development of agricultural machinery made it possible for fewer people

to do the same amount of work.

Thus, at the same time that the industrial revolution made it possible

to produce goods more cheaply and more quickly in factories, and

agricultural revolution also took place. Instead of leaving fields

empty every third year, farmers began to plant clover or some other

crop that would enrich the soil. Instead of using only animal

fertilizer, farmers began to use chemical fertilizers to keep the soil

rich. 49. These methods have enabled French farmers, for example, to

give five times as much wheat as was obtained from the same land two

centuries ago.