Drs. Normand, Reynolds, and Strang pose several important questions concerning our recent paper, "The Pulmonary Hypoperfusion Syndrome." We considered these and other questions bearing on the subject before submitting our preliminary report, and we plan to deal with them in our next paper. We feel that it is desirable, however, to comment on a few points now.
Drs. Normand, Reynolds, and Strang argue that the frequent occurence of respiratory distress in premature babies together with their observations that the amount of surfactant in the lungs increases with increasing maturity indicates a cause-effect relationship.