VI. FOOD-BORNE PATHOGENIC BACTERIA (_Continued_) 58 Paratyphoid Infection Typical Paratyphoid Outbreaks General Characters of Paratyphoid Infection Toxin Production Sources of Infection Means of Prevention VII. ANIMAL PARASITES 79 Trichiniasis Teniasis Uncinariasis Other Parasites VIII. POISONOUS PRODUCTS FORMED IN FOOD BY BACTERIA AND OTHER MICRO-ORGANISMS 85 Ergotism Botulism Symptoms Anatomical Lesions Bacteriology Epidemiology Prevention and Treatment Other Bacterial Poisons Spoiled and Decomposed Food IX. POISONING OF OBSCURE OR UNKNOWN NATURE 100 Milksickness or Trembles Deficiency Diseases Beriberi Pellagra Lathyrism Favism Scurvy Rachitis The Foods Most Commonly Poisonous INDEX 109 CHAPTER I INTRODUCTION How frequently food poisoning occurs is not definitely known. Everybody is aware that certain articles of food are now and again held responsible for more or less severe "attacks of indigestion" or other physiological disturbances that have followed their consumption, but in many cases the evidence for assuming a causal connection is of the slightest. That convenient refuge from etiological uncertainty, "ptomain poisoning," is a diagnosis that unquestionably has been made to cover a great variety of diverse conditions, from appendicitis and the pain caused by gallstones to the simple abdominal distention resulting from reckless gorging. No doubt can be entertained, however, that intestinal and other disorders due to particular articles of food occur much more frequently than they are recorded. There are few persons who have not experienced gastro-intestinal attacks of moderate severity which could be reasonably attributed to something eaten shortly before. It is often possible to specify with a fair degree of certainty the offending food. The great majority of such attacks are of a mild character, are quickly recovered from, and are never heard of beyond the immediate family circle. Only when the attack is more serious than the average or when a large number of persons are affected simultaneously does knowledge of the occurrence become more widely spread. A small proportion of food-poisoning cases receives notice in the public press and a still smaller proportion is reported in the medical journals. Very few indeed are ever completely investigated as to their origin.