Changes in middle ear after birth are observed in-

Ans. is 'a' i.e., Werdin's test * Werdin's test: Before birth middle ear contains gelatinous embryonic tissue which is replaced by air after respiratioTests used in infanticidePloucquet's test:* Weight of lung is measured in relation to body wieght. Before birth weight of lung is 1/70 of body weight and after respiration it becomes 1/35 of body weight due to increased blood flow in lung beds.Static test or Fodere's test:* The average weight of both lungs before respiration is 30-40 gm and after respiration is 60-70 cm.Hydrostatic test (Raygat's test, 1st life test):* The specific gravity of a non-respired lung is 1040-1050 and of a respired lung is 940-950, so, after respiration lung floats on water (specific gravity of water is 1000).* False positive hydrostatic test may occur (i.e.non-respired lung may float) in decomposition and in attempted artificial respiration.* False negative hydrostatic test (i.e. respired lung may sink down) may occur in atelectasis, pulmonary oedema, bronchopneumonia, and congenital syphylis.Breslau's second life test:* It assumes that a live born child would respire and therefore, would also swallow some air into the stomach and bowel.* Hence they float on water. This test is falsely positive in putrefaction (due to putrefied gases) or in cases of attempted artificial respiration.Werdin's test:* Before birth middle ear contains gelatinous embryonic tissue which is replaced by air after respiration.