Page:Blackwell 1898 Scientific method in biology.pdf/77

Rh medical belief) asserts that the diffusion of the cholera germ or cholera bacillus is not the chief cause of cholera. He states that there are two other absolutely necessary conditions, without which no outbreak of cholera is possible; and if these conditions are not present, the cholera germ may be breathed with no production of cholera.

The ﬁrst condition is the unhealthy state of the soil or locality. But even this does not produce an outbreak if the second condition does not exist, viz., individual predisposition; and he shows that neither the cholera germ nor the insanitary locality, nor both combined, will produce cholera if this individual predisposition does not exist. He further states that no experiments upon the lower animals can be relied on; the only proof in relation to cholera must be from the experience of human beings.

The supremacy of sanitation is the lesson which is being gradually taught by such humane scientific experiments. Dirt in its largest sense as matter in the wrong place, whether in air, water, food, clothing, habitation, soil, or contact, is undoubtedly a main physical cause of disease.

But in all epidemic disease the emotion of fear