ZYMOSIS of the ordinary kinds of fermentation, giving rise to a disease like typhoid fever. A univer- sal observation is that the origin of epidemics is often to be traced to the putrefaction of large quantities of animal and vegetable mat- ters; that miasmatic diseases are endemic in places where the decomposition of organic mat- ter is constantly taking place, as in marshy and moist localities ; that they are developed epi- demically under the same circumstances after inundations, and also in places where a large number of people are crowded together, with insufficient ventilation, as in ships, prisons, and besieged places. Factitious fevers, pro- duced by the introduction of deleterious sub- stances directly into the blood, are analogous both in their symptoms and pathological le- sions ,to those produced by the sting or bite of certain animals ; they present also the same general class of symptoms that are present in smallpox, scarlatina, and other eruptive dis- eases. Putrid animal exhalations have given rise to diseases that have raged like a pesti- lence or epidemic. Measles can be commu- nicated by means of a drop of blood from a patient affected with the disease ; the inoc- ulation of an unprotected person with small- pox may be the means of giving the disease to thousands ; and a mere trace of serum is sufficient to propagate cattle plague. Recent researches into the peculiar nature and origin of the fever poison, or "disease germ," have not done much toward elucidating the question. Spectroscopic examination of the contagious fluids, variations of temperature, symptoms of the patient, anatomical alterations, and mi- croscopic and chemical study of the blood upon the living and dead have furnished no notions sufficiently precise to draw any practical de- ductions. The most widely prevailing doc- trine of the present day respecting the origin and communication of disease is that known as the germ theory. Special organic forms known as mycrozymes, bacteria, bioplasts, &c., alleged by various pathologists to be found in contagious fluids, have been the subject of much discussion, some contending that they are of a fungoid growth and enter the body as parasites, others that they are germinal masses derived from normal cells, and due to a series of changes in existing matter under new circumstances ; while a third class deny positively that any such germs exist. The elements or factors giving rise to many of the conditions above mentioned are known as zy- motic, a term, like the atomic theory in chem- istry, not clearly descriptive, but admitted into the standard nomenclature of medicine as a convenient expression, and including all that class of diseases which can be communicated from existing foci, and which are capable of being prevented by hygienic and other con- ditions. The latest and most approved noso- logy includes seven principal diseases of the zymotic class and eleven others less common : smallpox, measles, scarlet fever, diphtheria, croup, whooping cough, continued fever (in- cluding typhus, typhoid, and simple continued fever), quinsy, erysipelas, puerperal fever, car- buncle, influenza, dysentery, diarrhoea, chol- era, ague, remittent fever, and rheumatism. The reports of the registrar general of Eng- land show that more than one fifth of the whole number of deaths is from zymotic dis- orders. An examination of the returns of the surgeon general and of the marine hos- pital bureau, as well as the health reports from the principal cities in the United States, will establish about the same ratio. This immense mortality, in view of the fact that all zymotic diseases are preventible, enforces the neces- sity of sanitary precautions. THE END.