Toxemia is a condition caused by the absorption of toxins from the bacterial activity. This is commonly known as blood poisoning. Sapremia Sapremia is a condition wherein the blood contains the putrefactive products of saprophytic and non-pathogenic bacteria. Epidemic When a great number of people are affected in a community by the same dis-ease in a short period of time it is said to be an epidemic. An epidemic is said to obtain when dis-ease breaks out suddenly and involves a number of persons at one time. There is a wide difference of opinion as to the percentage of individuals necessarily involved to constitute an epidemic. Endemic A dis-ease that is limited to a certain class of people or peculiar to a certain locality or district is said to be endemic. Endemic differs from epidemic in that epidemic refers to a dis-ease that is more or less constantly present. Sporadic A dis-ease occurring singly or affecting only a few people is said to be sporadic. Pandemic When an epidemic involves a large number of people in a large number of countries, it is known as pandemic. There is a question as to whether or not the word can ever be properly used. It is claimed that the influenza epidemic of 1918-19 could really be considered pandemic in view of the fact that the condition was found in all countries. These terms are used very loosely and are applied largely to suit the circumstances. A number of cases of a so-called contagious dis-ease occurring about the same time in a community may be considered an epidemic by some. There is no established rule designating the percentage of individuals that must be affected by the same condition in order that an epidemic may be established. An endemic dis-ease may become epidemic at certain times of the year or when a greater number of people than usual become affected. A sporadic dis-ease may become epidemic when a greater number of people become affected. Fomites Fomites are substances capable of absorbing and retaining infectious germs. The term is applied to inanimate objects and usually refers to bedding, especially mattresses, clothing and more particularly to woolen clothing. Such vectors, however, are not now receiving as much consideration as they did previously. It is no longer thought that such objects as books and furniture play any particular part in the spreading of so-called infectious dis-ease. The foregoing definitions will give the student understanding of the terminology in general use. We will now take up a consideration of the study of the subject proper of immunity. CHAPTER XI IMMUNITY IMMUNITY DEFINED NATURAL ACQUIRED ACTIVE PASSIVE EXHAUSTIVE THEORY OF PASTEUR RETENTION THEORY OF CHAVEAU VARIOUS THEORIES ADAPTABILITY OF THE BODY ENVIRONMENTAL CONDITIONS CARRYING CAPACITY OF THE NERVES RESERVE ENERGY VITAL RESISTANCE REDUCED CARRYING CAPACITY OF NERVES INTERFERENCE WITH TRANSMISSION