CHAPTER XII.
THE RAPID DEVELOPMENT OF MEDICINE IN THE LAST FIFTY YEARS .-- THE INFLUENCE OF DARWIN .-- PREVENTIVE MEDICINE .-- THE DISSEMINATION OF MEDICAL KNOWLEDGE .-- THE DEVELOPMENT OF CONDITIONS IN RECENT YEARS WHICH ACT AS FACTORS OF DISEASE .-- FACTORY LIFE .-- URBAN LIFE .-- THE INCREASE OF COMMUNICATION BETWEEN PEOPLES .-- THE INTRODUCTION OF PLANT PARASITES .-- THE INCREASE IN ASYLUM LIFE .-- INFANT MORTALITY .-- WEALTH AND POVERTY AS FACTORS IN DISEASE.
Certain conditions have arisen in the past fifty years which have profoundly affected the thoughts, the beliefs and the activities of man.

Within this period what is generally known as Darwinism, including under this evolution, has developed.

Unlike theories which came from philosophical speculation only, the theory of evolution was one which could be subjected to observation and experiment.

It freed man's mind from dogmas, it stimulated the imagination, it enlarged the territory in which it seemed possible to extend knowledge by the methods of science, and has resulted in an enormous increase of knowledge.

This has been more striking in medical science than elsewhere, and in this of more far-reaching influence.