A new science requires a new vocabulary and up to now the Hygienic principles have only been able to stutter in the language of old-school medicine. Its conceptions have not yet been naturalized in human language. A new conception of the essential nature, the rationale of "disease" needs a new terminology in which to express itself. If it is expressed in the old terms, it will be understood in these also. The old terms do not correctly express the facts as we now know them. More correct terms are, therefore, desirable.

One of the most essential first steps in the investigation of any subject of enormous complexity and extent, one that is necessary to a complete or satisfactory solution of even the most obvious difficulties presented by what we already know of the subject, is the careful separation of the distinctions that exist, and to cease confounding these distinctions under one word. Confounding distinctions under one phrase or word is a secret of wide delusions and prevents further unveiling of the complexities of the subject.

Words and phrases may be so vague and abstract as to signify anything or nothing. We must insist on a clear definition of the words and phrases used in our biological data and speculations. There can be no reasoning, no clearing up of truth, unless we keep definite words for definite ideas.

The perception of difference is the necessary foundation of all knowledge. Perhaps the best short definition of that in which essentially all knowledge consists is this: Knowledge is the perception of relations. To know a thing and to understand it, is to know it in its relations to other things, but the first step in such knowledge is to know it as distinguished from other things. The perception of mere difference precedes the perception of all higher relations.

Superficial resemblances may easily be mistaken for fundamental identity. We may choose to call two things one because we choose to look at them in one aspect only, and to disregard them in other aspects quite as obvious, and perhaps much more important. And thus we may create a unity which is purely artificial, or which represents nothing but a comparatively insignificant incident in the System of Nature.

Science is the reduction of natural phenomena to an intelligible order. This reduction has not been made in "disease". The one word is made to cover several distinct, though conjoined groups of phenomena. All reasonings on Nature would be hopeless unless we could separate in thought many things which are always conjoined in action. Careless and often studied use of an ambiguous language which confounds the deepest distinctions of Nature makes all but impossible a proper discrimination between two quite separate conceptions. There can be no reasoning, no clearing up. of truth, unless we keep definite words for definite ideas. No increase of knowledge can be acquired by a willful confounding or careless forgetfulness of distinctions.

The consideration of these and other points, which, as they occur to the writer, and, no doubt, to the reader, also, reveal, in an increasing manner, how very imperfect is our terminology and the need for a recreation of it. We must insist upon discrimination between very different things jumbled together and concealed under loose popular terms and phrases. I have attempted to create new terms to express the new conceptions and will try to define and explain them so that they may be understood by all.

To the defensive operations, both passive and active, of the body in throwing off the cause of its unhealth, I have applied the term biogony. It is from the Greek roots: bios, life; and agon, struggle, contest. Thus, it means the struggle of life. We could even define it as the "struggle to live".

To the damaged, deteriorated or degenerated condition of the body's tissues and fluids I have applied the old term, pathology. I use it, however, in the restricted sense here indicated and not as a word covering the whole range of phenomena commonly understood by "disease".

To the cause of the pathology, I have applied the term, pathogen, coined by Dr. Thomas Powel, but I use it in a broader sense than he did. It is used to mean any and all things that produce pathology.