The Goulstonian lectures on the typhoid bacillus and typhoid fever : delivered before the Royal College of Physicians of London on March 20th, 22nd, and 27th, 1900.

  • Hartley, Percival Horton-Smith, Sir, 1867-
Date:
1900
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Credit: The Goulstonian lectures on the typhoid bacillus and typhoid fever : delivered before the Royal College of Physicians of London on March 20th, 22nd, and 27th, 1900. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    but very definite slaty blue colour. Without going so far as to affirm that a typhoid bacillus could never give rise to such a change of reaction we may say at least that it can only rarely occur, and we should do well, therefore, to regard all such bacilli with grave suspicion until their identity with the typhoid bacillus has been otherwise most fully proved. We, may, then, affirm that the litmus milk test is of con- siderable value as a means of distinguishing the typhoid bacillus from the varieties of bacillus coli, if performed in the manner suggested, that is to say, if the culture is kept at 37° C. for at least one month. If discarded at the end of a week, as is the usual procedure, valuable indications are often lost. Indol test.—Another test commonly applied to distinguish the typhoid bacillus is the indol test, introduced by Kitasato 13 in 1889. The bacilli are grown in broth at 37° C , and the cultures are tested at the end of a variable time, generally one week, to see whether indol is present in them or not. Typhoid bacilli under these conditions never form indol, various members of the coli group do. If the test is to be of any real value, however, it must not be performed before the end of one month, for in many cases the forma- tion of the indol is much delayed. Even, however, if we take a month as the standard the test not uncommonly fails, and it should be noticed that this failure is especially common among the higher members of the group. Thus no indol was produced by any of the four members of the Gartner group which I have examined, and the test, there- fore, as a means of diagnosis becomes of infinitely less importance than the dextrose-agar or dextrose-gelatine test or the litmus milk test. Media of Capaldi and Proskauer.—We now come to two tests for the typhoid bacillus which are too little known. I refer to the media introduced by Capaldi and Proskauer.34 Into their composition I need not enter; suffice it to say that in Medium I. the bacillus coli grows readily and forms strong acidity, while the typhoid bacillus will not grow at all; in Medium II., on the contrary, while both grow readily the typhoid bacillus alone forms acid. The tests, like all the others which we have been discussing, have their limitations; but that they are of considerable value is shown by the fact that by means of them two of the four members of the Gartner group which I have examined, as well as Houston’s four bacilli (bacillus typhosus simulans, a, b, c, and d), were at once differentiated from the typhoid bacillus. In these media, then, we have a valuable auxiliary means of distinguishing the typhoid 13 Ibid., Band vii., 1889, p. 515. 14 Ibid., Band xxiii., p. 471.