Pancreatic gland cells = Trypsin = Albuminoids changed to peptones in alkaline solutions. Disease germ = Toxin: Enzyme = Morbid phenomena. Disease germ = Contagious disease. Further consideration of pathogenic microörganisms will be found in connection with contagious diseases. MEDICAL DIAGNOSIS. Means of diagnosis. Usual health of the subject. History of the attack. Objective symptoms, interdependent disease, fever, diseases that may be confounded, subsidiary disease, diagnostic signs, organ involved, pathological test injections, course of disease, sporadic or zymotic, result of treatment. Diagnosis is the determination of the seat and nature of a given disease and its distinction from other morbid conditions. Its importance to the practitioner cannot be overestimated as it occupies the pivotal position between causes, nature, morbid phenomena, and symptoms on the one hand, and prognosis, prevention, and treatment on the other. Unless the conclusions are sound as to causes, nature, lesions, and symptoms, there can be no certain diagnosis, and without a correct diagnosis, prognosis, prevention, and treatment can have no intelligent or scientific basis. The practitioner who finds a dropsical condition and who is satisfied to pronounce it dropsy and institute treatment is abusing his trust. He must find whether this dropsy results from disease of the kidneys, heart, bloodvessels, lymphatics, liver, lungs, bowels, or the structures in which it is shown; whether it is due to parasites or imperfect sanguification or to other morbid conditions, before he dare prescribe treatment and predict results. So in every other affection; the failure to make a correct diagnosis opens to the practitioner many doors of error, and he is happy indeed if he can escape the injuring of his patient. In seeking a sound diagnosis we must attend to the following among other indications: 1st. The habitual state of health of the subject. The genus, breed, age, environment, habits, (pet dog, watch dog, hound, sheep-dog, ox, bull, cow, milch cow, sheep in the field or housed, pig in pen or at large, diet, regimen, water, race horse, draught horse, work, exposure, etc.) as well as the personal equation of temperament, idiosyncrasy, heredity, etc., must all be carefully considered. 2d. The history of the present illness as to its apparent cause, mode of invasion, duration and progress.