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The micro-organisms of the mouth include species belonging to higher orders than the Bacteria or Schizomycetes. I have therefore used the wider term Mycology, in preference to Bacteriology, as the title of the present work.
Bacteriology has developed to such an extent that at the present time some fifteen hundred organisms have been described and a large proportion of them are to be met with occasionally in the mouth. It is impossible to include in the scope of the present work, all the bacteria found from time to time in the oral fluids, especially as environment, food, dust and other causes determine to a great extent the species of the buccal flora ; at the same time a certain number of organisms, many of them well known to bacteriologists in other situations, are so frequently found that they deserve consideration as mouth bacteria ; a few bacteria and some higher forms related to the Hyphomycetes are to be found in the mouth only, I have therefore included in the following pages those bacteria frequently living in the buccal cavity although they are also found in other places, and those special organisms so far known in no other region than the mouth. An attempt is made for the first time to produce a practical text-book dealing with mouth bacteria, and although primarily intended for the use of students of dental surgery it is hoped the collection of facts related to the Mycology of the Mouth may be of assistance to those engaged in research. As the work is mainly written for students a good deal of stress is laid upon the practical details of laboratory routine, bacteriology requiring more laboratory experience perhaps than any other subject. General principles of biology, sterilization, &c., are also given at some length, for only with a thorough knowledge of general principles is it possible to attempt the study of individual organisms and the student is advised to
master general facts before proceeding to minute descriptions of the organisms themselves.
In bacteriological work a definite plan should be followed both for the benefit of the student and for the interests of the science at large ; recognised methods should always be adopted in the first place, and full details of others accurately given, the plan given in the text and the suggestions on the “ Study of Cultivations,” will, it is hoped, prove useful guides.
The pathogenic bacteria of the mouth are given at some length and are of great importance in the relation of pathological conditions of the mouth to general disease, a relationship long since recognised by dental surgeons competent to judge, although the subject has only recently received the general attention it deserves. Mouth pathology with probable, but so far undescribed bacteriology, is only too common and it is hoped tbat by calling attention to the gaps in our knowledge others may be induced to investigate these undetermined problems.
Several of the organisms given in the latter portion of the book may possibly be synonymous, but as so far I have had no opportunity of carefully testing all, the descriptions originally given are adhered to. The question of immunity is touched upon and a general statement of fact given, but it is impossible within the scope of a text-book of this description to discuss the matter in full; my intention is rather to give the main points without going deeply into the subject.
Fermentation and Dental Caries are so closely related that a good deal of space is devoted to their consideration; a general resumé of dental caries from the point of fermentation physiology is naturally associated with the description of the bacteria involved in what is a special form of metabiotic putrefaction.
In dealing with the special mouth bacteria references are given to the original papers to which the student has the opportunity to refer if he so wishes.
In the appendix are given some practical hints on the choice and use of the microscope, and the scheme for a system of describing cultivations of bacteria recently suggested by Chester in his “ Determinative Bacteriology," definite but general terms taking the place of lengthy descriptions, the latter often proving inaccurate from the variation of individual organisms. The system has much to commend it.
In writing this book the various standard text-books have been freely consulted, among them may be mentioned : “ Sternberg's Bacteriology," " Macfarland's Pathogenic Bacteria,” “Muir and Ritchie's Text-book of Bacteriology,” “Miller's Micro-organisms of the Human Mouth,” and the works of Lefar, Hueppe, Du Barry, Plugge, Migula, Lehman and Neumann, and others.
In conclusion, I acknowledge with many thanks the loan of a number of illustrations, which are duly acknowledged.
My thanks are also warmly accorded to my friend, Dr. J. W. Eyre, for many valuable suggestions and for the performance of many inoculation experiments at various times.
Mr. Cyril Hill has also kindly assisted in photographing apparatus and in the matter of proofs.
KENNETH W. GOADBY.