The apparent increase in the incidence of pulmonary abscess, especially the postoperative form, has become a serious problem for both surgeon and physician. There are two important theories regarding the cause of pulmonary abscess, the embolic and the aspiration theories. At present each has about an equal number of adherents. The evident conflict between these theories is an obstacle to the adoption of satisfactory methods of prevention. Consequently, it would seem advisable at this time to attempt to appraise their relative value.
Included among the chief supporters of the embolic theory are Fetterolf and Fox,1 and Cutler2 and his associates. Cutler, in a series of ingenious and well controlled experiments, produced pulmonary abscess in the dog with infected emboli. However, he was unsuccessful in his attempt to produce a similar condition in dogs by the aspiration route. He concluded from these observations that most cases of postoperative abscess