AUTO-INTOXICATION (SELF-POISONING).—A type of poisoning which may take place in the body of an animal or a plant as a result of its own metabolism. In all plant and animal growths, certain products appear which, unless modified, would poison the plant or animal. Thus, in all plants oxalic acid is formed as a necessary step in the building up of starches and sugars. The plant protects itself from poisoning by neutralising this acid with calcium salts, forming insoluble calcium oxalate crystals. The human body protects itself constantly in a variety of similir ways. Thus, in the very act of breathing, when the oxygen of the air enters the red blood-cells, the carbon dioxide formed by the oxidation in the tissues is eliminated, and life is made possible.
As a result of tissue metabolism many acids (sulphuric, acetic, etc.) are formed in the human body ; and these acids, if not neutralised and elimi nated, as in the urine, would give rise to poisoning. The liver is a very active organ in looking after the necessary oxidations and reductions in the human body ; and it is largely due to the integrity of this organ that auto intoxication does not more readily occur. There are few really well-known examples of true auto-intoxication in man ; and the countless cases described by quacks and charlatans are for the most part pure nonsense.
Among the diseases that are thought to bear a close relationship to auto intoxication are the following : (t) Those caused by the failure of chemical function of some organ, as the pancreas (in bronze diabetes); the thyroid gland (in rnyxzdema cretinism : exophthalmic goitre [?„); the pituitary body (in acromegaly); and the blood-making organs (in pernicious anaemia). (2) A second group result from imperfect combustion and elimination. Diabetes is an illustration. Gout may be another. (3) Retention of a product produced in a true physiological process, as in carbon dioxide poisoning in heart affections. (4) Excessive production of poisons, with insufficient neutralising powers, as in the acid intoxication of diabetes in which all the alkalies of the body are utilised to overcome the excessive amounts of organic acids formed. Other factors are at work, but those enumerated are sufficient to indicate the general subject. Poisoning from constipated retention of f2ecal products is not here concerned. This is
really a poisoning caused by agents outside of the body.
AUTOPSY.—The examination of a dead body in order to determine more minutely and more accurately the causes of death. The public should insist on having autopsies performed on all dead bodies, such examinations being of service to the people at large by affording physicians the oppor tunities for studying diseases more closely.
BACTERIA.—Name given to a class of simple plants, the relation of which to disease processes has become of immense importance. Bacteria are exceedingly minute, one-celled plants, often less than of an inch in diameter ; they have no green colouring matter (chlorophyl) like higher plants, and they grow by a process of splitting. In the plant scale they are grouped with fungi, and they belong among the very lowest members, being intermediate or transitional alga: Nvhic II have become parasitic.
With regard to shape, three main groups of bacteria are distinguished : (r) Coccacem (spherical forms), micrococcus, diplococcus, streptococcus, staphylococcus, and sarcina being the names of the genera ; (2) (rod-shaped forms), divided into bacillus (with flagella) and bacterium (with out flagella) ; and (3) Spirilla (spiral forms). Other forms are known, but with regard to these a reference to some text-books on the subject may suffice (see Migula, System der Bakterien Rolle and Wassermann, Handbuch der Pathogenen lifikroorganismen : Muir and Ritchie, Bacteriology).
The properties that are of prime importance in the bacteria are con nected with their life history. In their struggle for existence they have elaborated a number of chemical substances (ptomaines, toxins, etc.) which act as poisons on,the human body, destroying it by causing complex changes in many of the vital organs. The changes that may be induced by these bacteria and by their poisons are numerous, and the large subject of bacterial pathology cannot be here considered ; as a rule, however, they either cause slight changes in the blood so as to render it incapable of carry ing on its functions, or their poisons so affect the nervous centres that they cannot keep up their activities.