Manual of Bacteriology

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VF. RELATIONS OF BACTERIA TO DISEASE?THE PRODUCTION OF TOXINS BY BACTERIA. Introductory.?It has already been stated that a strict division of micro-organisms into saprophytes and true parasite cannot be made. No doubt there are organisms, such as tho bacillus of leprosy, gonococcus, etc., which are...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VF. RELATIONS OF BACTERIA TO DISEASE?THE PRODUCTION OF TOXINS BY BACTERIA. Introductory.?It has already been stated that a strict division of micro-organisms into saprophytes and true parasite cannot be made. No doubt there are organisms, such as tho bacillus of leprosy, gonococcus, etc., which are in natural conditions always parasites associated with disease. But these can lead a aprophytic existence in specially prepared conditions, and there are many of the disease-producing organisms, such as the organisms of typhoid and cholera, which can flourish readily outside the body, even in ordinary conditions. In fact we may ay that probably the cultivation of all pathogenic organisms on Artificial media is only a matter of time. The conditions of growth are, however, of very great importance in the study of modes of infection in the various diseases, though they do not form the basis of a scientific division. A similar statement applies to the terms pathogenic and nprophytie, and even to the terms pathoi/enic and non-pathogenic. By the term pathogenic is meant the power which an organism has of producing morbid changes or effects in the animal body, either under natural conditions or in conditions artificially arranged, as in direct experiment. Now we know of no organisms which will in all circumstances produce disease in all animals, and, on the other hand, many bacteria described as harmless saprophytes will produce pathological changes if introduced in sufficient quantity. When, therefore, we speak of a pathogenic organism, the term is merely a relative one, and indicates that in certain circumstances the organism will produce disease, though in the science of human pathology it is often wed for convenience as implying that the organism produces disease in man in...