If these methods fail, an examination of the stools for tubercle bacilli must be made; and if they are found, they cannot be consid ered due to an intestinal lesion. They may equally well have been swallowed and have their source in a tuberculosis of the tonsil or of the lungs. Strassburger's sedimentation method is used to detect the bacilli. This consists in mixing a small amount of stool with water, adding alcohol or alcohol and ether to the supernatant fluid, then allowing it to settle and examining the sediment for bacilli.
We must also not neglect to look for bacilli in the sediment of the urine. They may be found not only where tuberculosis of the urinary tract exists but at times when the disease is located elsewhere. Examination for tubercle bacilli in sputum, in the urinary sediment, in feces, and in the stomach contents is best carried out as follows: 1. Spread the material as thin as possible, allow it to dry, and fix by passing through the flame three times.
2. Stain for two minutes with carbolfuchsin, holding it over the flame until the solution begins to steam [fuchsin 1 Gm. dissolved in 10 c.c. of absolute alcohol, to which 100 c.c. of carbolic acid (5 per cent ) is added].
3. Wash with water.
4. Decolorize for about 30 seconds in a hydrochloric acid-alco hol mixture (10 c.c. cone. hydrochloric acid, 990 c.c. 70 per cent. alcohol).
5. Wash with GO per cent. alcohol until all the red color is removed.
6. Counterstain with weak aqueous methylene blue solution for 1-2 minutes (1 c.c. cone. aqueous sol. of methylene blue to 10 c.c. of distilled water).
7. Wash and dry with filter paper.
If the excreta show no tubercle bacilli, we may resort to an examination of the blood. For this purpose, 1-2 c.c. of blood are obtained from the median vein and injected either intraperitoneally or, if we are anxious to know the result more quickly, into the mam mary gland of a guinea-pig which is suckling its young. However, even if the blood contains bacilli, we shall probably not discover the fact until the patient has died. Nevertheless the method is of value to establish the diagnosis when we do not believe an autopsy will be granted.
Lumbar puncture may show the bacilli in miliary tuberculosis in spite of the absence of all clinical symptoms which might point to an involvement of the meninges.
If the find the bacillus in one or other of the above ways, the diag nosis is established. However, if we do not find it, as is so often the case in the early stages, we may resort to the second method, which consists in the Diagnostic Injection of Tuberculin.
Robert Koch discovered in 1890 the fact that certain constituents of the tubercle bacillus have the property of causing specific reactions in the tuberculous individual, when subcutaneously injected.
The agent used to establish this reaction he called tuberculin. At the present time it is often referred to as "old tuberculin." The official name is tuberculin= Kochi, and when the term tuberculin is used, it should be understood that it is this preparation that is referred to. It is a clear brown fluid which, in accordance with Koch's directions, is prepared from cultures of the tubercle bacillus in glycerin bouillon by filtering ofT the bacilli and compressing the filtrate into one-tenth of its volume. Its essential constituents are the soluble secretory products of the tubercle bacillus. In Germany the manufacture of the preparation is under State control, and 1 c.c. of it costs M. 1.50 (40 cents).
In order to obtain the reaction, tuberculinum Kochi is diluted with water without any antiseptic, and the best method is to prepare, under aseptic precautions, a solution of 1:100, which is again adequately diluted before injection. The mother solution of 1: 100, if preserved in the dark and at a low temperature, will keep a few days. Caution, however, should still be exercised, as a slight turbidity will indicate that the preparation is no longer effective. The injection is made into the subcutaneous cell tissue of the back or abdomen, the place of puncture having first been suitably prepared.
Prior to the test injection of tuberculin it is necessary to make sure of the afebrile condition of the subject. 1 always have the temperature taken twice during the twenty-four hours preceding the injection, and if the same should exceed 37.5° C. (99.5° F.), I absolutely decline to inject.
The dose depends upon the condition of the patient.. The test injec tion should never he commenced with more than 0.001 grain and, as a rule, it is even better to reduce the same to 1- or is this quantity, thus commencing with 0.0001 gram. This holds especially good for all cases in which there are manifestations of pulmonary infiltration or there is suspicion that the lungs arc involved by the tuberculous process. In these cases the first test injection had better be reduced to 0.00001 gram, the injection repeated, and if this should be negative, the injections may be continued with five or tenfold doses, and so on.