Tuberculosis; a treatise by American authors on its etiology, pathology, frequency, semeiology, diagnosis, prognosis, prevention and treatment.
- Arnold Klebs
- Date:
- 1909
Licence: Public Domain Mark
Credit: Tuberculosis; a treatise by American authors on its etiology, pathology, frequency, semeiology, diagnosis, prognosis, prevention and treatment. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![Morphology of the Tubercle Bacillus.—The morphology of the tubercle bacillus varies according to its origin, the length of time it has been grown on artificial culture media, the composition of the cul- ture media, and the age of the individual culture examined. Two types of bacilli are found in man, the human and the hovine. The human bacillus is a slender rod 0.3 /x in thickness and from 1.5 fx. to o fi long, its length being from about one fourth to one half the diam- eter of a red-blood corpuscle. Longer forms are sometimes met with. The rods are straight or curved and occur singly, in pairs, or in small bundles. In old cultures, filamentous clubbed and branched forms are not infrequently seen. The bacilli often stain unevenly, presenting a beaded appearance, due to unstained areas along the rod with deeply stained portions between them. The bovine ])acillus is shorter than the human organism, seldom being more than 2 ju, in length, and is somewhat thicker. The rods are straight and often spindle-shaped. Very short forms are common, the length being not more than twice the thickness. They take the stain evenly and deeply, beaded forms not being common, though sometimes seen, especially in tissues. The two types are quite tenacious of their characteristics, but tend to approach each other under prolonged cultivation, the bovine bacillus coming to resemble the human more closely. Capsules of Schron.—These are round, oval, or elliptical bodies, from 1 /* in diameter to 5-6 fi long and 2-3 /u, in breadth, the largest exceeding greatly the tubercle bacillus in size. They stain deeply with carboi-fuchsin but decolorize by Gram's method. They are found in tuberculous tissues, especially glands, quite frequently, and are believed to be involution forms of the tubercle bacillus. Walsham states that they are sometimes seen in pure cultures of the tubercle bacillus. Staining.—The tubercle bacillus stains with difficulty, owing to the large amount of fatty or waxy matter it contains (ten to forty per cent), but having once taken the stain, resists decolorization strongly, a characteristic which enables one to distinguish it readily from the vast majority of other bacteria. In the examination of sputum one can usually be safe in depending entirely on this characteristic, but when examining feces and urine or certain tissues, further precautions must be taken which will be spoken of later. Various stains have been proposed for demonstrating the tubercle bacillus, but the great superiority of the Ziehl-Neelsen carboi-fuchsin stain over all others has led to its practically universal adoption. Saturated alcoholic solution of fuclisiii 11 c.c. Solution carbolic acid in water (five per cent). . 100 c.c.](https://iiif.wellcomecollection.org/image/b21216423_0051.jp2/full/800%2C/0/default.jpg)
