A very interesting brief case report, entitled "Pulmonary Hyaline Membranes and Vascular Anomalies of the Lung," was published in Pediatrics by Bozic. This case is commonly referred to as the "Lausanne baby" and is used by many to support the hypothesis that hyaline membrane disease is primarily related to reduced pulmonary blood flow. Although there are good reasons from observations in both man and animal to implicate reduced pulmonary blood flow as an important factor in the pathophysiology of hyaline membrane disease, we do not believe the "Lausanne baby" can be used to support this hypothesis.