CELLULAR ELEMENTS. 65 



with the usual blood stains, but there is little doubt that normal 

 milk contains these so-called pus cells, and it is only when they 

 are present in excessive amount that pus is indicated. Sometimes 

 true blood-corpuscles are found in milk, but these are due to 

 the actual presence of blood, either through a turgid condition 

 in the early stages of lactation, a slight mechanical injury, or 

 a diseased condition of the udder. 



