Absolute leucocytosis in acute pneumonia comes on rapidly with a chill, oscillating slightly during the disease, and disappears at about the time of the crisis. This disappearance of the leucocytosis is one of the critical phenomena of the disease, The leucocytosis in acute pneumonia is above all a polynuclear leucocytosis. The polynuclear averages about eight-five per cent in moderately severe cases, ninety-two per cent in serious cases, and ninety-five per cent in fatal cases. The gradual ascent of the polynuclears indicates an almost fatal prognosis. There is a parallelism between the crisis of the leucocytosis and the urinary crisis; i. e., the reappearance of the chlorides in the urine. There is a relation of cause to effect between the leucocytosis, the peptonuria, and the elimination of uric acid. These two phenomena are directly produced by the setting over of leucocytic nucleins and the resolution of the exudate. The rare forms of cells which are found in the blood of pneumonia are abnormal forms which appear on the sixth day, the basophile after them, and the eosinophile which appear after them more or less rapidly. The abnormal form and the basophile announce the cure which the eosinphile affirm. The author states that he does not wish to insist upon the absolute character of these deductions, but states that they are of almost absolute certainty, or at any rate are extremely probable.

The author concludes by stating that he considers the increased number of polynuclears not as an indication of resistance, but as one of invasion of the organism. It is a measure of invasion and not a measure of resistance.

The Detection of the Typhoid Bacillus.-E. H. HANKIN in the Centralblatt für Bakteriologie for November 16, 1899, calls attention to a method for isolating the typhoid bacilli from drinking water. The method consists in adding one, two, three or four drops of Parietti's solution to tubes containing ten cubic centimetres of neutral bouillon. Each tube is then infected with a few drops of the suspected water. According to the old method of using Parietti's solution, the tube showing the most cloudiness after the end of twenty-four hours would have been picked out for examination for the typhoid bacillus. Hankin, however, does not pick out the most cloudy tube, but the one next below this in cloudiness, and from it he inoculates a second group of of bouillon containing Parietti's solution. In this second group of tubes the smallest amount of Parietti's solution added is that equivalent to the amount present in the tube of the original set from which the culture is taken. In the second set of Parietti's tubes, as in the first, the one next below the cloudiest one is selected, and from this cultures are made on litmus sugar agar. At the end of forty-eight hours these organisms which have not turned the litmus agar red are examined. Only those which morphologically resemble the typhoid bacilli are tested. The author was able by this means to isolate the typhoid bacillus in several instances, from drinking water which had caused typhoid fever, something which, as is well known, has seldom been done. The bacilli so isolated were subjected to careful tests, and were also submitted to Pfeiffer and Wright who confirmed the author's diagnosis of typhoid bacillus.

The Antibacteriological Value of Acrolein-In the Centralblatt für Bak teriologie for November 16, 1899, KOCH and FUCHS give the result of their examinations of this new antiseptic. The substance belongs to the same group as formaldehyde, but differs from it in being an aldehyde of allyl alcohol, whilst formaldehyde is an aldehyde of methyl alcohol. The new substance acrolein boils at 52.5° centigrade, and is easily soluble in a strength of twenty-five per cent. in water. The authors tested the substance in one-quarter, one-half, one, two and five per cent. solutions upon various micro-organisms, such as the bacillus pyocyaneus, the colon bacillus, and the pus cocci. They conclude that one can say in general that acrolein is a stronger disinfectant than formaldehyde, and that as far as it has been tested it also gives good results in the disinfection of large rooms.

Pathogenic Micro-Organisms in the Air.-E. CONCORNOTTI in the Centralblatt für Bakteriologie for November 7, 1899, discusses the question of the number of pathogenic organisms found in the air. He examined in a large number of cases the air from private houses, hospitals, railroad cars, and various other places. His examinations were conducted by exposing culture media to the air for a given length of time, allowing bacteria to develop, washing the surface of the media with sterile water, and then inoculating animals. In forty-six inoculated rabbits fifteen died of infection of the staphylococcus aureus. Of the same forty-six rabbits, eight died of infection with the staphylococcus albus, six of infection with the bacillus coli communis, and two of infection with the diplococcus of pneumonia.

From his studies the author concludes that by inoculating animals intravenously with washings from agar plates, pathogenic organisms are much more easily detected than by some of the old methods. Pathogenic organisms which are found in the air are in accordance to the order of their frequency, the staphylococcus aureus, the staphylococcus albus, bacillus coli communis, and diplococcus of pneumonia. These pathogenic organisms occur most frequently in places with dirty surroundings, whether these be public or private.

ALBANY

MEDICAL ANNALS

Original Communications

THE PREPARATION OF TUBERCULIN, ITS VALUE AS A DIAGNOSTIC AGENT, AND REMARKS ON THE HUMAN AND BOVINE TUBERCLE

BACILLI.*

BY VERANUS A. MOORE, M. D.,

Professor of Comparative Pathology and Bacteriology, N. Y. State Veterinary College, Cornell University, Ithaca, N. Y.

The hope formerly entertained that tuberculin, or, more correctly speaking, Koch's old tuberculin,† possessed a specific therapeutic value has been dissipated in the realization of the fact that its unquestioned usefulness is that of a diagnostic agent. While its character and properties are generally understood by the medical professions, there are still those who doubt the experimentally tested and practically demonstrated possibilities of this substance. Of the bacterial products which in recent years have come into prominence, few if any occupy a place, either in human or comparative medicine, where an accurate and widespread knowledge of the conditions limiting their effectiveness is more urgently demanded than for tuberculin. The important position it holds in sanitary medicine, and the powerful agent it may become in the hands of those who have to do with bovine tuberculosis, emphasize the necessity of such a knowledge.

Within the limits of this paper, it will be impossible to discuss in detail the numerous questions which naturally suggest them

* Read by invitation before the Medical Society of the State of New York, Albany, January 30, 1900,

It is important not to confound the tuberculin which was discovered by Koch in 1890 with the new tuberculin described by him in 1897. For a brief description of this new product see appendix.

Maragliano (Berliner klin. Wochenschrift, May 1, 1899) describes a watery extract of tubercle bacilli which he calls aqueous tuberculin.

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selves in the effort to give an account of the present knowledge of tuberculin, what it is, and what it will do. I purpose, however, to treat somewhat fully of the more essential features in its preparation and in its use, which, if thoroughly understood, seem sufficient to answer many of the objections to its employment as an aid in detecting tuberculosis in cattle. Much of the honest opposition to its use, in this state at least, seems to come from a lack of definite knowledge of its true nature and powers.

At the outset it is important to note that we are dealing with a problem in which the chief factors are unmeasured and, to a certain degree, unmeasurable vital forces. In the very beginning, we are confronted with the manifestations of life itself. The problem is one in biology where unexpected deviations may occur as a natural, though unexplained, result of the immediate conditions of life. If this fundamental principle is taken into account it will teach us that many of the objections to tuberculin which have been held up as insurmountable because they were not immediately explained to the satisfaction of the objector can not, from the very nature of things, be explained until we have more knowledge of the mysterious processes of life and disease.

Tuberculin, as we know it to day, is the concentrated liquid, usually glycerinated bouillon, on which tubercle bacilli have grown until they will grow no longer, that is, the products resulting from their multiplication and imparted to the medium have inhibited their further development. It is not definitely determined just what these products are or just how they are elaborated. Briefly stated the preparation of tuberculin consists of the following procedures, viz.:

(1) The preparation of the culture medium, distributing it in suitable flasks and inoculating it with the growth from a pure culture of tubercle bacilli.

(2) The flasks are placed in an incubator at a temperature of about 37° C. where they remain until the growth ceases. The length of time necessary to accomplish this depends upon the age and condition of the culture from which the inoculations were made. From four to ten weeks are usually required.

(3) After the maximum growth is attained the cultures are sterilized by heat, either by boiling in a closed water bath or heating to a higher temperature in an autoclav.

(4) After the sterilization the cultures are filterel to remove all of the dead bacilli, and the filtrate is evaporated, to the desired degree of concentration, over a water bath.

(5) The concentrated liquid is passed through a Pasteur or Berkefelter filter, standardized, bottled for distribution, and labelled with the name, quantity, and size of dose. It should be perfectly clear although the color may vary. If it is cloudy it should be rejected when received.

A careful consideration of these various procedures assures one that each and every step requires skilled attention. It is logical at least to presume that if each part in the process is not carefully looked after the product may, to that extent, be unreliable. Of the possible errors in its preparation, the danger of using too young cultures, that is before the required degree of saturation of the bacterial products takes place is. perhaps, the one most liable to occur. For example, if the flasks of bouillon are inoculated from an old culture several weeks may elapse before the new growth begins, but if a young growing culture is used it begins at once, or better, continues with but slight interruption as in the mother flask. However, unfavorable conditions of medium or temperature may retard these growths. It is usually the delay in getting the tubercle bacilli to begin to multiply in the newly inoculated medium that causes the variation in the length of time necessary to incubate the cultures before they contain the proper amount of the tuberculin elements.*

If the method of preparation is further examined, it will be seen that tuberculin cannot possibly contain living tubercle bacilli.

It is heated to a temperature and for a length of time far in excess of that required to destroy them on two occasions besides being passed through a filter capable of removing all bacteria. It is a physical impossibility, therefore, for tuberculin, which has been properly made, to cause tuberculosis. Whatever physiological disturbances it may excite, it can not impart that which it does not possess, namely the contagium vivum of the disease.

The original tuberculin or lymph of Koch was concentrated to one-tenth of the volume of the saturated cultures. This gave a thick syrupy liquid owing to the presence of the glycerine. The occasional reports of poor tuberculin may be explained in this way. Early in my experience with tuberculin, a quanity was made from vigorous cultures that had been incubated for the full time. When it was tested it failed to give a reaction. Upon seeking an explanation the notes showed that the growth in the flasks taken was retarded for three weeks and very feeble for two more. Subsequently an excellent tuberculin was made form the same original culture.