He estimated how many species of insects lived on each plant species in England, and then extrapolated that figure across the whole planet. âIf we say 400,000, we shall, perhaps, not be very wide of the truth,â he wrote. Today, scientists know the Westwood figure is far too low.
Symptoms: A chronic dry cough that's worse at night, disturbing sleep, and sometimes with wheezing and shortness of breath. Causes: An irritating night cough is often the first sign of asthma, especially in children, but you can develop it at any age. It's also a sign asthma is worsening or not being well controlled.
Sounds like: A dry cough that ends with a rattle or wheeze. People with asthma have inflamed airways, which can cause difficulty breathing as well as wheezing and coughing. Other telltale symptoms: The cough gets worse at night or while exercising; chest tightness; shortness of breath; fatigue.