3. Capability to control the causes. With astonishing speed once the initial breakthroughs had occurred, sera and vaccines were developed to control many of the lethal microbial diseases that had plagued earlier generations. Improved dietary practices, pasteurization of milk, personal hygiene and above all, environmental sanitation to rid drinking water of polluting pathogens, all advanced rapidly in the final quarter of the 19th century and the first few decades of the 20th century.