Good healthy lung tissue will resist the germs, and the only way to have good healthy lung tissue is to use the lungs properly.
Consumptives are nearly all narrow-chested.

What does this mean?
Simply that these people were addicted to improper habits of breathing, and consequently their chests failed to develop and expand.
The man who practices the Complete Breath will have a full broad chest, end the narrow-chested man may develop his chest to normal proportions if he will but adopt this mode of breathing.

Such people must develop their chest cavities if they value their lives.

Colds may often be prevented by practicing a little vigorous Complete Breathing whenever you feel that you are being unduly exposed.

When chilled, breathe vigorously a few minutes, and you will feel a glow all over your body.