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 cough may be described as being dry, wet, productive (meaning you cough up mucus and/or sputum), or non-productive. Even the way a cough sounds can give us a pretty good clue as to what is going on. A dry cough may be caused by an allergy, cold, flu, or the beginning of bronchitis. A wet, productive cough could be the result of pneumonia, bronchitis, or the flu. A wet, nonproductive cough may also suggest a cold, flu, or bronchitis. A painful cough is frequently seen with pneumonia or bronchitis.