INFECTION.--An agent by which disease may be communicated from one individual to another; also, an infectious disease.

INOCULATE.--To introduce any biological product directly into the tissues of the body.

INOCULATION.--The process of inoculating.

INTESTINAL TRACT.--The small and large intestines.

M

MICROBE.--See _Germ_.

MICRO-ORGANISM.--See _Germ_.

MUCUS.--The substance secreted by mucous membranes.

MUCOUS MEMBRANES.--The membranes lining certain cavities of the body, especially the digestive and respiratory tracts.

N

NUTRIENT.--One of several chemical groups to which the essential const.i.tuents of food belong.

O

ORGANIC.--Derived from or relating to an organism.

ORGANISM.--An individual that is or has been alive.

P

PARASITE.--An individual that lives in or upon another individual.

PASTEURIZATION.--The process of pasteurizing.

PASTEURIZE.--To subject milk to a temperature of 142-145 Fahrenheit for thirty minutes.

PATHOGENIC.--Disease-producing.

PERTUSSIS.--Whooping-cough.

PROTEID.--One of the complex nitrogenous substances const.i.tuting the essential parts of animal and vegetable tissues.

PROTOZOoN (pl. protozoa).--An animal organism composed of a single cell.

PUS.--The fluid product of inflammation; matter.

PUTREFACTION.--Decomposition of nitrogenous organic matter brought about by micro-organisms and accompanied by a foul odor.

R

RESISTANCE.--See _Immunity_.

RESPIRATORY TRACT.--The air pa.s.sages, including the nose, mouth, larynx, trachea, bronchial tubes, and lungs.

S

SAPROPHYTE.--A vegetable organism that lives on decaying organic matter.

SARCINA.--Literally, a bundle. Applied to bacteria grouped in bundles or packets.

SEPTIC.--Putrefying or decomposing; infected by pus-producing bacteria.

SEQUELA.--A disease or unhealthy condition following another disease or unhealthy condition.

SERUM.--The fluid which separates from the clot after blood has coagulated; especially, that containing an ant.i.toxin.

SEWAGE.--Any substance containing urine or fecal matter; also, the substance which pa.s.ses through sewers.

SPIRILLUM (pl. spirilla).--A variety of bacteria having spirally twisted cells.

SPORE.--A resting stage, characterized by great resistance, into which certain germs enter when conditions become unfavorable for their growth.

SPUTUM.--Spit; expectoration.

STAPHYLOCOCCUS.--A variety of bacteria that group themselves in ma.s.ses resembling bunches of grapes.

STERILE.--Free from living germs; aseptic.

STERILIZATION.--The process of rendering sterile.

STERILIZE.--To render sterile.

STREPTOCOCCUS.--A variety of bacteria that arrange themselves in chains.

STUPE.--A cloth wrung out of hot water and applied to the surface of the body.

SUSCEPTIBLE.--Lacking resistance to a disease.

SUSCEPTIBILITY.--The condition in which resistance to a disease is low.

T

TETRAD.--A variety of bacteria that arrange themselves in groups of four.