The presumed reason for concluding that approximately 10-15 percent of drowning victims die without aspirating water is that the victim experiences laryngospasm, chest-wall spasm, or both when submerged, thus dying without taking a breath. The original studies referenced for this phenomenon are by Cot, who reported his work in the French literature in 1931. Because all animal experiments the authors could find in the literature that are descriptive of the drowning process include a period of ventilation underwater prior to death, and because the authors were unable to find evidence in animals subjected to the complete drowning process that the lungs were void of the characteristic frothy/foamy material that accompanies water aspiration, they question whether the conclusion of "drowned without aspiration" is valid. The absence of free water in the lungs of a person who is found dead in the water is not uncommon. The authors believe that not all of these persons drowned. The presence of pulmonary edema per se is also found in persons with a variety of other conditions, such as pulmonary infection, chronic pulmonary disease, cardiac failure, and trauma from cardiopulmonary resuscitation. This type of edema, however, is of a much finer quality and does not exhibit the frothy, foamy variety that is seen in the alveoli, bronchioles, bronchi and/or trachea of someone who has drowned. 36 references