Examination should be delayed for more than a few hours especially when amoebae are to be looked for. Naked eye examination Quantity - Bacteria usually make up one third to one half of the dry weight of faeces. Bulkier stools occur with vegeterian diet. Colour - Normal faeces are light to dark brown in colour due to the presence of bile pigments.
Coloured stools occur in obstructive jaundice due to absence of bile pigments in the stool.
Tarry or black stools occur in upper gastrointestinal haemorrhage due to altered blood. Tarry stools also occur following iron administration. Consistency - Normal stools are well formed. Watery stools occur in diarrhoea. Hard faeces suggest constipation.