Organisms have recently been divided into two great groups,—those which can only grow in dead or decaying matter and those which can grow in the living tissues and in the blood, which in this relation must be looked upon as a tissue. The first group has been termed “saprophytic.” The second group may be termed “pathogenic,” to distinguish them from the saprophytic variety. But no distinct line of demarcation can yet be drawn between these two groups, and as a matter of fact some pathogenic organisms may equally with the saprophytic find a pabulum in dead and decaying matter. Yet there can be no doubt that the more common varieties of septic organisms or saprophytes can only grow in dead or decaying matter, and that the living tissues, more especially when their power of vitality is great, are able to resist and destroy the saprophytes. There are also some organisms which, as far as is known at present, may be innocuous and give rise to no symptoms, local or general, when they are implanted in the human body. When an organism finds in the tissues a fit pabulum for its growth and development, the elements in the tissue are broken up, and the products are termed a “ptomaine” (τrτω∕χα). This ptomaine may irritate the wound and prevent healing; it may also be absorbed into the blood and poison it, hence the term “ptomaine poisoning.” Both the saprophytic and the pathogenic organism may form a ptomaine in the wound. When the wound is due to a saprophyte the absorption of the ptomaine has been termed “sapraemia”; the ptomaine of the saprophyte has been called “sepsin.” No special name has yet been given to the ptomaine formed in the wound by the pathogenic organism; nor has any name been given to the condition due to the absorption of the ptomaine formed by the pathogenic organism. Our knowledge is not yet sufficient to enable us to separate these two varieties of ptomaine poisoning. There can, however, be little doubt that they do exist as separate conditions, and also there can be little doubt that in some instances both forms of poisoning may be present at one and the same time.

The pathogenic organism, however, has another power which gives rise to an entirely separate condition. Not only may it form its ptomaine in the wound, but the organism itself can enter into and be carried by the bloodstream and lymph-stream to distant parts. It can live in the blood or lymph-stream and can grow there: it may be arrested in the capillaries of the blood-vessels, or in the lymphatic glands of the lymph-vessels, and in these situations may form, so to speak, a colony of organisms which develop and form ptomaines; and the ptomaines, passing into the blood, may still further poison the patient. This power of the pathogenic organism is infective, and the term “infection” has been applied to the process. These colonies or secondary foci of infection often go on to suppuration; hence the term “secondary” applied to the abscesses which have long been observed in some forms of blood-poisoning. It was at one time thought that the pus-cells in the original wound passed into the blood, and, being caught in the capillaries, were the cause of the abscess-formation in the parts distant from the wound; hence the term “pyaemia” or pus in the blood. The pus-cells may enter the blood-stream; it is not, however, the cellular element that is the essence of the condition, but the organism which the cellular element may carry along with it. The hectic condition observed in a case of long-continued suppuration is in all probability a chronic form of blood-poisoning. In very acute cases, in which the poison is either concentrated, virulent, or in large quantity, death may occur within a very few hours. In other cases the condition may become chronic, and if the strength of the patient can be kept up by stimulants recovery often takes place. The chances of recovery are much greater when the condition is not truly an infective one. When the manufactory of the ptomaine is only in the wound, the organism may be there destroyed by the use of powerful antiseptics or antifermentatives. The primary cause being removed, the patient may then be saved. When, however, the pathogenic organism gets into the bloodstream and distant foci of infection are formed, the chances of ultimate recovery are greatly diminished. Various unsuccessful attempts have been made by the internal administration of antifermentatives so to alter the blood that the micro-organism cannot find in it or the tissues a fit nidus. The point to attend to is to prevent organismal fermentation in wounds by careful antiseptic or rather antifermentative precautions. Just as the word “septicaemia” has a more general application than can now be strictly allowed if we look to the derivation of the word and the present state of our knowledge, so the word “antiseptic” is applied to all substances which prevent organismal fermentation, although many of these organisms are undoubtedly non-septic in their character.