The standardisation of tuberculin / by A.J. Eagleton.

  • Eagleton, A. J.
Date:
[1921?]
Catalogue details

Licence: In copyright

Credit: The standardisation of tuberculin / by A.J. Eagleton. Source: Wellcome Collection.

    7/12 (page 5)
    both in the length of time taken to become sensitive and in the degree of sensitivity attained, as judged by the minimal lethal dose of standard tuberculin. The earliest period at which any batch is sensitive can only be found by a preliminary test as described above, and in some batches as many as five such tests have been negative. Again, if 0-5 c.cm. of standard kills one or two animals of a batch we have to inject lower doses to find the degree of sensitivity present; in this way many animals are wasted. In order to obviate this difficulty we tried both the von Pirquet and intracutaneous tests parallel with the subcutaneous test. As a result of many experiments we found a correlation between the three methods, as shown in the table (vide infra). 2. The von Pirquet Test. Yon Pirquet himself studied the cutaneous reaction of tuberculous guinea-pigs to tuberculin ; he states that these animals are not very sensitive to the drug, and that a deeper scarification is necessary than that used for the test in human beings. Our experiments confirm this, but we found that when deep scarification was used the resulting trauma sometimes made the reac¬ tions difficult to read. We changed our method of scarification from two intersecting parallel lines to two and finally three parallel scratches ///, and the “ three- scratch ” test is the one we now employ. With this method the trauma is not sufficient to obscure the reaction, and well-graduated readings can be obtained with different dilutions of tuberculin on the same animal. Before the tests, a white area of the animal is deprived of hair by clipping and the application of a calcium sulphide paste, after which the area is washed with warm water and the animal thoroughly dried. The groups of three scratches are spaced out as far as possible. Different dilutions of the tuberculins are applied to the areas, and glycerine broth, ten times concentrated as in the preparation of the tuberculin, is used as a control. The reactions can be read in 24 hours, and have generally diminished by 48 hours. 3. Intracutaneous Reaction. The intracutaneous reaction was first described in 1905 by Mantoux, Moussu, and Romer, and adopted later by Loewenstein, but is not used in any official laboratory. The test consists in the injection of 0T c.cm. of diluted tuberculin into the skin of the shaven area. As in the von Pirquet test, we have always used a control of broth, but in this case diluted 1/10. The reactions cannot be read