A text-book upon the pathogenic bacteria : for students of medicine and physicians / by Joseph McFarland.

  • McFarland, Joseph, 1868-1945
Date:
1903
Catalogue details

Licence: Public Domain Mark

Credit: A text-book upon the pathogenic bacteria : for students of medicine and physicians / by Joseph McFarland. Source: Wellcome Collection.

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    the proper opportunity (avenue of entrance and entrance in sufficient number) to bring about their familiar effects. (a) Skin and Mucous Membranes.—It would be as use¬ less as tiresome to compile a list of the bacteria that may be found upon the skin. The very fact that the skin surface is extensive, external, slightly moist, and constantly in contact with external objects ought to be sufficient guarantee that almost any bacterium may be found upon it. Certain forms, however, predominate over all others, and of these it is probable that Staphylococcus epidermidis albus (Welch) is the most widely distributed. Staphylococcus pyogenes albus and Staphylococcus pyogenes aureus are also quite common. Bordoni-Uffreduzzi found that some of the odors of the skin are peculiar to micro-organisms that inhabit it. Thus, he found that cultures of his Bacillus graveolens, isolated from between the toes, gave off the disagreeable odor characteristic of “dirty feet.” Streptococcus pyogenes is also sometimes present upon the skin. It is improbable that bacteria placed upon the skin can penetrate its uninjured structures. Only microscopic in¬ juries are necessary, however, to admit them, and infection can be produced by rubbing the bacteria into the skin, if it be slightly abraded in the process. Any wound—a puncture, incision, laceration, abrasion, insect bite, etc.—that destroys the perfect continuity of the epithelium may become a point of entrance for bacteria. The bites of animals and insects may cause infection from bacteria contained in the saliva. It has been sup¬ posed that plague infection might result from the bites of parasites. Nuttall,* however, investigated the subject in relation to anthrax, chicken cholera, and mouse septi¬ cemia, and found that when bed-bugs, fleas, etc., were first permitted to prey upon infected and then upon healthy mice, the latter did not become infected even when the biting insects were so pressed upon as to play the role of injecting syringes. The bacilli of the diseases mentioned occurred in vast numbers in the excrement of the insects as long as ninety-six hours, then disappeared, losing their virulence and vitality before this period had passed. It therefore becomes doubtful whether plague or other diseases are frequently spread in this manner. In the soft, moist, mucous membranes it does not seem * “Centralbl. f. Bakt. u. Parasitenk.,” April 12, 1898, xxiii, No. 14.
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