An argument for a mathematics program that is more compatible with the nature of the learner is therefore an argument for a greater degree of involvement with manipulative materials and exploitation of appropriate mathematical applications.
The Germ theory of disease, developed in the 1860s and 1870s by Louis Pasteur, states that tiny living beings are the cause of infectious diseases. The theory was developed to explain puerperal fever, or Child bed fever.
The germ theory was proposed in the mid-16th century and gained widespread credence when substantiated by scientific discoveries of the 17th through the late 19th century. It supplanted earlier explanations for disease, such as Galen's miasma theory.