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.
This new concept of germs being causal agents of disease had its earliest supporters among plant pathologists like Tillet for bunt in 1755, Prevost for smut in 1807, Berkeley and de Bary for the late blight fungus of potatoes in the 1850s (13).