Germfree animals and technics in surgical research. Germfree animals have been reared to a size, weight, and age permitting the performance of major surgical procedures and the pursuit of a variety of surgical research problems. Germfree dogs have been maintained in the isolator system through three generations, indicating that life, reproduction, and growth are all possible in the absence of microbial contamination. The value of the germfree approach to surgical problems has been utilized in studies of a variety of gastrointestinal problems, shock, cancer, immunology, burns, wound healing, and in direct patient application. Patients have been maintained in isolator environments for prevention of infection, for operative procedures, for treatment of extensive burns, and for management of immune-suppressed individuals. We conclude that germfree animals and germfree technics provide a valuable addition to the armamentarium of the surgeon in both research and clinical applications. 