THE VALUE OF CLINICAL PATHOLOGY TO THE

PRACTITIONER.

A. R. DIEFENDORF, M.D.,

MIDDLETOWN.

The rapid and phenomenal progress in medicine during the past few decades has been almost wholly due to investigation in the field of pathology. As a result of this, pathology and its technique has taken a prominent part in the training of the general practitioner. Courses in pathology in the medical schools have been lengthened and strengthened, and whereas formerly these courses consisted almost wholly in demonstration, they now include practical training in the actual technique of the examination of the blood for parasites, the estimation of the number of blood-corpuscles, the isolation and identification of different bacteria, the examination of throat-cultures and purulent discharges.

These recent acquisitions in medical science have placed the older practitioners at a distinct disadvantage. Unable to acquire the requisite knowledge by reading alone, or to spend the time and money to procure a special training and the expensive instruments needed in this work, some have entirely ignored this valuable adjunct to successful practice depending upon their intuitive knowledge gained by extensive experience; while others with great enthusiasm but meager knowledge have turned to the pathologist with everything from an onychia to hemicrania, and have accepted his report as the sine qua non. While to some it may seem that the present day tendency in medical teaching is to produce pathological enthusiasts to the detriment of a well-rounded medical education, practical experience with recent graduates

shows that even these clinicians fail to regard and utilize their pathological training in the proper light, and with the proper spirit.

It is the object of this paper to bring these two factions into closer touch with clinical pathology, to enthuse the pathological pessimist and to subdue his counterpart, the enthusiast; and furthermore to place those who are not able to undertake pathological work themselves, in a position where they can correctly interpret the pathological report as it comes to them from the man who examines the material.

I purpose to consider briefly the diseases in which microscopical examinations are most often needed by the practitioner to aid him in his treatment, prophylaxis and prognosis. These will be divided into the diseases in which (1) bacteriological examination is necessary; (2) those in which blood-examinations are necessary; (8) those in which material from the intestinal tract is necessarily examined; (4) those in which urinary analysis is most important.

This classification is necessarily unsatisfactory as some bacteriological diseases need blood-examinations and some intestinal, and urinary disorders demand other examinations than those of the stomach contents, feces and of the urine in order to arrive at a positive conclusion.

TUBERCULOSIS.

Among the bacteriological diseases, tuberculosis with its wide distribution and high death-rate naturally demands the aid of the pathologist more often than any other disease.

In suspected pulmonary tuberculosis the sputum, whatever its quantity or character, should be examined. One sometimes finds that the most innocent looking saliva is swarming with tubercle bacilli, and on the other hand sputum suspiciously turbid, tenacious and filled with small white bodies fails to reveal the specific organism.

In collecting material for examination precaution must be observed if absolutely reliable results are to be obtained, that only a very clean receptacle be employed, the expectoration made into the bottle containing some water, preferably sterile water, and well stoppered, particularly if the specimen is to be transported some distance. In case it is desirable to determine the presence of a secondary infection, it is very necessary both that the material be collected in sterile water and examined very shortly after collection. A positive report is always positive and sufficient, but a single negative report should mean nothing. If the characteristic bacteria are absent from the early morning sputum, then specimens from other periods of the day should be examined, and finally a twenty-four hour specimen should be collected. One is justified in any suspicious case in making repeated examinations through several months if negative results are found.

Meanwhile an estimation of the number of white blood. corpuscles may give a valuable clue as to the diagnosia. Most uncomplicated tubercular affections are not accompanied by a leucocytosis. The exception to this rule is found in tuberculous meningitis, where a a moderate leucocytosis occurs in over fifty per cent. of the cases. The presence of a leucocytosis, therefore, would indicate that the affection was probably not tuberculous, or if tuberculous, it existed either in the form of tuberculous meningitis or complicated with pus formation, such as pulmonary cavities or a general infection, tuberculous peritonitis or salpingitis.

In suspected tuberculosis of the urinary tract; tuberculosis of the bladder, prostrate or kidney, a careful examination of the urine is most essential, the object being to determine the presence of tubercle bacilli in the sediment. To accomplish this several examinations may be necessary. Here also a positive report is always posi tive, care having been taken to differentiate the smegma

bacillus, but a negative report means little unless a most painstaking examination has been made, or a guinea-pig injected.

Finally, in tuberculosis of the intestinal tract, a careful search for the presence of the tubercle bacilli must be made, and a report to be positively negative must include an injection of a guinea-pig.

The serum agglutination test of Arloing for tuberculosis, which three years ago gave promise of such brilliant results, has thus far failed to give the anticipated results.

TYPHOID FEVER.

In typhoid fever the pathologist by means of the Widal Reaction, the bacteriological examination of the blood and the leucocyte count may be of great assistance to the clinician in the recognition of the disease.

The employment of the Widal test as now used is not practicable for the practitioner himself unless he has a rather extensive bacteriological outfit, so he is compelled to depend upon established private or public laboratories for its application.

A positive report on this test from a laboratory is to be relied upon as a very sure diagnostic point. The qualifications to bear in mind are that the positive reaction indicates a typhoid infection, past or present, and this infection may be a latent process existing in the gallbladder, in the bone-marrow, or urinary bladder. The latter is a rare complication and so can be readily ruled out, while in regard to the residuals of old attacks of typhoid it may be said that the blood of such individuals usually loses its agglutinative power in two years, but cases have been reported where it has remained over twenty years.

The receipt of a negative Widal report by a practi tioner necessitates the consideration of several factors. In the first place there are at least four to seven per

cent. of so-called cases of typhoid fever in which there is never a Widal reaction. These cases are considered by some investigators as being due to a bacillus allied to the typhoid bacillus and called the paratyphoid bacillus, yet to all practical purposes such cases to the clinician are genuine typhoid fever, demanding the same prophylaxis and treatment as that form of disease arising from the true typhoid bacillus.

But in ninety-three to ninety-six per cent. of cases one may expect a positive reaction within the first ten days. In only a very small per cent. of cases does a positive reaction occur for the first time after the tenth day. Some cases have been reported in which the positive reaction did not occur until during a relapse. In view of the fact that the reaction only infrequently takes place previous to the sixth day, a negative report up to this time has no value, but negative reports continuing up to the eleventh eliminate the probability of typhoid in most

cases.

A method of more certain diagnostic value than the Widal reaction is the isolation of the bacillus from the peripheral circulation where it may be found as early as the second day of the disease. A sufficient number of observations has not yet been carried out to permit of a statement of its absolute value. The difficulty of technique in this method, which requires the withdrawal of at least four c. c. of blood from the vein of the arm and a considerable amount of media, renders it less valuable for general use.

Others recommend the isolation of the bacillus from the rose spots or from the feces, but either of these methods is unsuitable for general use.

The leucocyte count of the blood in suspected cases of typhoid fever is of distinct value, indeed there are few diseases excluding those recognized as diseases of the blood, per se, in which a blood-count is of more value. In contra distinction to almost all other local inflam