effort to procure sleep, are foes to slumber. A light supper taken about 2 hours before retiring is in many cases conducive to sleep. People with feeble circulation should guard against cold feet, a common, cause of sleeplessness, by the use of bed socks or hot water bottles.
INFECTION, CONTAGION, AND INFECTIOUS AND CONTAGIOUS DISEASES
Contagion, a name derived from the two Latin words, con and tango to touch together, is the term applied to the substance which communicates disease from an unhealthy person to a healthy one when there is actual contact. The word infection is applied to the vehicle by which a malady is transmitted from one person to another by the air, and with or without actual contact. The type of infectious disease is small-pox, and this is also, as is well-known, a highly contagious complaint. Scarlet-fever, measles, whooping-cough, mumps, etc., are likewise both contagious and infectious, and make up the class of disorders popularly known as diseases which are "catching."
The most probable doctrine of the true nature of contagion is that set forth in the germ theory of disease. This hypothesis, which has exercised a most important influence on modern medicine and surgery, accounts for the symptoms of contagious diseases by attributing them to the more or less mechanical irritation of groups of microscopic plants (bacteria), and in some cases minute animal micro-organisms, developing in the blood, the skin, and the vital organs of affected persons.
The period of incubation (by which is meant the time between exposure to small-pox, for example, and the outbreak of the complaint) is supposed to correspond with the time required for the sprouting of the seeds of these minute plants within the body. The gradual increase in the severity of the symptoms is attributed to the progressive growth of millions of tiny vegetable organisms, whose period of greatest luxuriance marks the height of the attack, and the death and destruction of which correspond to the decline of the disease.
Germ Theory.—The contagiousness of the communicable maladies is accounted for by the existence of the immense number of almost inconceivably small micro-organisms, which are constantly produced by and given off from the sick person, and carried through the air of a room or house either alone or attached to the innumerable epithelial scales which are all the time being rubbed off, as dandruff, etc., from our bodies.
The general absence of second attacks has been explained by the hypothesis that a substance is produced in the blood by the first attack, which is detrimental to the life of the micro-organism. This substance is called an antitoxin. Another explanation is that the micro-organism,