Modern surgery, general and operative / by John Chalmers Da Costa.

  • Da Costa, J. Chalmers (John Chalmers), 1863-1933.
Date:
1907
Catalogue details

Licence: Public Domain Mark

Credit: Modern surgery, general and operative / by John Chalmers Da Costa. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    through the opening. A cell usually contains but one spore, which may be situated at the end of the cell {endspore) or in the middle of the cell {endospore). Sometimes a single cell contains several spores. If an endspore exists,,the end of the cell containing the spore is swollen or club-shaped {drumstick bacterium). If an endospore exists, the cell becomes spindle-shaped {Clostri- dium). When multiplication is by a single endospore, the bacillus does not elongate. When multiplication takes place by a process of combined spore- formation and fission, the mother-cell divides into a number of daughter-cells, which are called arthrospores. Organisms which when active multiply by fission take on spore-formation when subjected to certain conditions. Spore-formafion tends to occur when bacilli are about to die for want of nourishment or when there is an excess of oxygen present. The spore has a dense envelope or covering which is very resistant to destructive agents. So resistant is the covering that twice the amount of heat is necessary to kill a spore as to kill an active adult cell. Spores when placed under conditions unfavorable for development may remain inactive for an indefinite period, just as seeds remain inactive when unplanted. When spores encounter favor- able conditions, they at once develop into adult cells, just as seeds develop when planted. It seems probable that spores occasionally remain dormant in the human body for long periods, and finally awaken into activity because of injury or disease of the tissue in which they lie. Chemical Composition of Bacteria.—The protoplasm of bacteria consists of water, salts, albuminous material, extractives soluble in alcohol, and extractives soluble in ether. Life=conditions of Bacteria.—In order to grow and to multiply, bacteria require a suitable soil and the favoring influences of heat and moisture. The soil demanded consists of highly organized compounds rather than crude substances, and slight modifications in it may prove fatal to some forms of bacterial life, but highly advantageous to others. ■ Some organisms require albuminous matter, others need carboh)-drates; they all require water, carbon, nitrogen, oxygen, hydrogen, and certain inorganic materials, especially lime and potassium (Woodhead). All organisms require water. If dried, no micro-organisms will multiply, and many forms will die. The fluids and tissues of the individual may or may not afford a favorable soil for the germs of a disease, or, in the same person, may afford it at one time and not at another. Some individuals seem to possess indestructible immunity from, and others are especially prone to, certain bacterial diseases. Impairment of health, by altering some subtle condition of the soil, may make a person liable who previously was exempt. Injury or disease of a tissue may increase local liabiHty. Again, some bacteria which under normal conditions are harmless may become virulent under certain conditions. Colon bacilli, which under nor- mal conditions seem to be putrefactive organisms inhabiting the intestine, may attack a point of least resistance in the intestine itself; this point being estab- lished by congestion, strangulation, inflammation, or injury, and descendants of the bacteria which attacked the point of least resistance may become so viru- lent that they can live and develop in tissues distant and apparently normal and cause disease in them. The presence of oxygen influences microbic growth. Most organisms