The use of toxic gases during the recent World War introduced a new subject in medicine. The clinical effects and the acute pathologic lesions of these gases have now been quite thoroughly investigated, but very little is known concerning what chronic lesions may remain after all symptoms have subsided. The need for further knowledge on this subject is apparent to all concerned in the care of sick veterans or in the fixing of compensation for soldiers who have been gassed. Because there is little opportunity to gain this knowledge from studies on soldiers who were the victims of gas attacks, this series of experiments on animals has been carried out.
We have attempted to determine whether pathologic lesions persist in the lungs of dogs which have been gassed but which have recovered from all symptoms. We had hoped to study the pathologic physiology as well as the pathologic anatomy of