Diphtheria and its associates / by Lennox Browne ; illustrated by the author.

  • Browne, Lennox (Isaac Lennox), 1841-1902.
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: Diphtheria and its associates / by Lennox Browne ; illustrated by the author. Source: Wellcome Collection.

    104/320 (page 78)
    7» /)//'/////AAV,/. In from fourteen to eighteen hours—if the case he one of true diphtheria—the colonies of the hacillus first become apparent and characteristic; and, in the opinion of Roux, if there be no such appearance within twenty-four hours, a negative diagnosis may be formed,—at least as to that particular culture. But here again we are not justified in saying that the membrane under examination has not been formed by the diphtheria bacillus, until repeated cultures have been made from it. Method 3. Presuming that our colonies have developed, how are we to know that they are those of the diphtheria bacillus ? After the culture tubes have been in the incubator at a temper- ature of 35° to 37° C. for fourteen to eighteen hours, colonies of the diphtheria bacillus appear, as whitish-grey specks, each about the size of a pin's head; the contour is regular and the surface dry. By transmitted light the centre of the colony is seen to be fchicke] and more opaque than the periphery, which is translucent. An almost positive diagnosis of the presence of the diphtheria bacillus is therefore established, that is to say, a positive naked- eye diagnosis has been obtained. Method 4. After twenty-four hours other microbes form colonies, and may complicate the diagnosis; for example, the colonies formed by the Brisou coccus bear a certain resemblance to those of the bacillus diphtherias; but they are smaller, the surface is moist, and their periphery is more opaque than the centre. The microscope, of course, is the sine qtta ?ion of accurate distinction between them, and should always be employed to control the diagnosis. The Brisou cocci appear as diplococci and cocci in rosettes, threes, fours, &c. (Fig. 10). The streptococcus is of much slower growth, and its colonies