The examination of 1 he urine in cases of suspeeted typhoid is of value provided it are recognized: the reac tion is more constantly present in ty phoid than the Widal reaction ; in the majority of instances the diazo-reaction is present 4S hours earlier than the Widal reaction; it disappears early, and, there fore, results obtained later than the sec ond week are of little value; doubtful reactions have slight significance. J. S. Billings. Jr. (New York Med. Jour., April 15, 1903).
Previous to the introduction of Widal's test the diagnosis of typhoid fever was sometimes confirmed by the finding of the typhoid bacillus in the blood from the spleen or from the rose-colored spots. These methods have been superseded and are not now employed. The same might be said of Elsner's and Capaldi's methods of cultivating the bacilli from the stools of typhoid patients.
The diazo-reaction of Erhlich is still considered a valuable test. Two solu tions are used: one a saturated solution of sulphanilic acid in a solution of hydro chloric acid (50 cubic centimetres to 1000 cubic centimetres), the other a cent. solution of sodium nitrite. The test is made as follows: To a small quan tity of urine in a test-tube an equal quan tity of the sulphanilic-acid solution and a solution of sodium nitrate is added. A solution of ammonia is now allowed to flow down the side of the test-tube. It forms a clear layer above the urine and at the junction a layer of reddish color will be noticed. When the tube is shaken the foam presents a well-marked pinkish tinge. The test is readily applied, but has the disadvantage of being present in malaria, tuberculosis, and in some febrile conditions.
The diazo-reaction appears in many diseases, but is constant in measles and typhoid fever. In the latter it bears a distinct relation to the severity of the case. It arises as a result of absorbed intestinal toxins of the disease, which become changed in the blood and furnish the reaction in the urine. Its disappear ance indicates early improvement when other signs of this change are wanting, while its reappearance is a sign of re lapse. Certain drugs produce it, but these may be distinguished from the genuine reaction by its slightness, and by the absence of the green precipitate. Its presence with Widal's reaction is a positive sign that typhoid fever is pres ent. Isz6 Honig (Klinisch-therap. Woch.,
Aug. 5, 1900).
Modern methods of examining the blood may be of value in diagnosis. Thayer is of the opinion that ("Post-ty phoid Alumina," page 109) the examina tion of the leucocytes may be of great value. The examination of a fresh specimen of the blood may exclude malaria by the absence of the Plas modium malarice. In tuberculosis with local inflammation and in acute tuber culosis there is an increased leucocy tosis.
In the absence of leucocytosis and the change in the relative proportion of the different varieties of colorless corpuscles one to another we have two valuable points, which, while neither may be pathognomonic, are of considerable di agnostic value.
The differentiation between typhoid fever and malaria has already been re ferred to. The therapeutic test, the administration of quinine, will some times distinguish between the two dis eases.
Lobar pneumonia of the pneumococ cic origin may be difficult to distinguish from that produced by the typhoid ba cillus. The methods already mentioned, Widal's reaction and the blood-examina tion, will be sufficient if one is only on his guard to make the tests. Pyfemia from some concealed source is often mis taken for typhoid fever, and the tests just mentioned are of great value. Sep tic endocarditis may closely resemble typhoid.
The approach of the organism, on the one hand, to the typhoid bacillus and, on the other, to the colon family is well shown by the cultured properties. The effect on milk and the non-production of indol are like the typhoid bacillus, and in the fermentation of glucose it resem bles the colon family.
Bacillus coli communis possesses to a marked degree the power of reducing neutral red, producing a canary yellow fluorescent color of the medium. The so-called bacillus enteritidis of Gaertner also produces this reaction, and is prob ably only a variety of bacillus coli com munis.
The bacillus typhosus never possesses this power of reduction, nor do the com mon pathogenic micro-organisms give it. By means of neutral red it is possible within from twelve to twenty-four hours to diagnose with absolute ac curacy the presence of bacillus coli communis. As far as personal experi ence goes, it is possible to diagnose by means of neutral red the true coli group from the typhoid group of micro-organ isms. William Hunter (Lancet, Mar. 2, 1901).