Heparin (Continued)

To the Editor.—  I agree with Dr. Wilson that the assay of heparin has always posed a difficult problem because the mechanism by which the hypercoagulable state develops from the pulmonary megakaryocytes is not appreciated. And whether one neutralizes heparin with protamine sulfate or checks whole blood coagulation with the highly unreliable Lee-White method or, as has been done for many years in England, with the Dale and Laidlaw coagulometer, the assay can be misleading, chiefly because the amount of clottable substance to be neutralized can vary.It is most important that heparin prophylaxis with the use of commercial heparin preparations of both beef and pork varieties has reduced fatalities to almost zero. This heparin prophylaxis is successfully monitored with the modified Dale and Laidlaw tube, maintaining levels at normocoagulation only. I believe our clinical success is what must convince others and not the speculative statements, if lives are to