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.
A dry cough often occurs in conjunction with other symptoms, which vary depending on the underlying disease, disorder or condition. Other symptoms include fever, shortness of breath, and chest pain. Symptoms including sounds the lungs make while you are breathing, changes in blood pressure, and low blood oxygen levels may only be evident using certain instruments in the doctorâs office or hospital.