Koch’s Lymph

[after Robert Koch, a German bacteriologist]. See Tuberculin. K.’s Method of Sterilization, a method of interrupted heating. The culture-media are heated for a short time daily for from three to five succe ive days, usually in the steam-sterilizer. K.’s Rules, rules formulated by Koch that must be complied with before a given microorganism can be accepted as the cause of an infectious disease: I. The microorganism must be present in every case of the disease, and not in cases of other diseases. 2. It must be isolated and grown on artificial media. 3. Its cultures when injected into an animal-body must produce the disease in question. 4. The microorganism must again be found in the body in which the disease was thus produced. 350