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.
Dry Cough: Causes and Simple Home Remedies. Dry cough (definition) is a type of cough that does not produce sputum or phlegm. It can be triggered by infections and cold (the most common causes of dry cough), allergic reactions, traumas, lung cancer, airway obstruction, and other abnormalities. In most cases of chronic dry cough, inflammation is an important feature. In cases of difficulty breathing, fever, chest pain, heart palpitations, night sweats, or swollen legs or ankles, the situation can be life-threatening and you need to seek immediate medical help.