There are mostly metaplastic cells, which are affected by chlamydia, show a dense usually cyanophilic cytoplasm with vacuolization. They are characterized by more or less round granula, sometimes also amorphous inclusion bodies. The vacuoles are multiple and mostly perinuclear, sometimes the nucleus is pushed aside like a signet-ring cell. Also columnar cells of the endocervix may be infected by chlamydia. They are showing more less characteristic signs, mostly a fine vacuolated cytoplasm. A smear of the endocervix, wet fixed, stained by Papanicolaou, allows the suspected diagnosis "chlamydia-infection", if metaplastic or endocervical cells show these characteristic changes. The proof diagnosis however is only possible by cell-culture.