In 196 cases where the physicians made a definite diagnosis of "not diphtheria," true diphtheria bacilli were found in 90 cases, and none in 88. In other words in nearly half the cases, which physicians were sure, were not diphtheria, true diphtheria bacilli were found. Therefore, while it is highly probable that factors not here considered enter into the relation between the clinical and bacteriological diagnosis, it is very evident that not all the cases diagnosed clinically as diphtheria are so in fact, and that a very much larger number of cases which clinically are not called diphtheria, are in reality mild or moderate cases of that disease.

While bacteriological work, carried on previous to the establishment of municipal laboratories had shown that it was impossible to make an accurate clinical diagnosis in every case, the Municipal laboratory system has succeeded in placing these facts before the larger proportion of the medical profession in a clearer, more definite manner than could have been accomplished by any other means.

Not to make a correct diagnosis in a case of true diphtheria may cause a serious epidemic of the disease, and to make a diagnosis of diphtheria where no true diphtheria bacilli are present means an unnecessary quarantine, which frequently carries with it considerable financial loss as well as avoidable annoyance and hardship.

Not only is the diagnosis of diphtheria important, but after it has been established it is very essential to know when the patient ceases to be a source of danger to others. It is probably safe to assume, that when no diphtheria bacilli can be found in cultures, made directly from the former location of the disease, that they are not present to the extent that will be dangerous to others. In no other way can the time when a patient ceases to be a source of danger to others, be determined as the character or severity of the disease gives no indication of the probable duration

of the bacilli. It has often been observed by us that the bacilli persist for a longer period in some mild cases than in some very severe ones.

In 843 cases shown bacteriologically to be true diphtheria we were able to estimate the time from the outset of the disease to the day on which a culture showed the disappearance of the bacilli. The longest duration was 112 days and the shortest 4 days. The average was 29.1 days. The average duration of 448 cases in the Municipal Hospital was 37.5 days.

Not only to physicians and their patients is the examination of cultures of value but it also gives reliable information to those in charge of the administration of the quarantine regulations, and such regulations are of the greatest importance, for it is only by means of a thorough quarantine that the disease is kept in check.

The Examination of Sputum from Suspected Cases of Tuberculosis.

This work consisted in the examination of 394 samples sent to us through the police stations or left at the laboratory by physicians.

This work is of value chiefly to the patients and their attending physicians. As pulmonary tuberculosis has not yet been officially declared to be a communicable disease no record of the patient's name and address or clinical diagnosis and history is kept or asked for, and consequently no comparison of the clinical with the bacteriological diagnosis can be made.

BUREAU OF HEALTH-LABORATORY OF HYGIENE.

Philadelphia,......

DEAR DOCTOR:—The Examination of the Sputum marked...

.189

If at any time cases of this disease are required to be registered or are kept under observation by authorized nedical inspectors, this laboratory will be in a position to render nearly as valuable services to all concerned as it now does by its diphtheria diagnosis work.

The Production of Diphtheria Antitoxin.

The method used in this work is the same as is used by all those producing a reliable remedy.

Diphtheria toxin is prepared by growing, for 6 or 7 days in incubators kept at the body temperature, special virulent diphtheria bacilli, in boullion, specially made from decomposed meat, and after the addition of two per cent. of peptone, bringing the reaction to the neutral point, with litmus paper as the indicator, and then adding 7 c.c. of a normal soda solution to every litre of the bouillon.

At the end of the specified time the bouillon cultures are filtered through several layers of filter paper, and onehalf of one per cent. of carbolic acid is added to the clear filtrate to preserve it.

Such toxin is injected subcutaneously or deeply into the muscles of young healthy horses in progressively increasing doses. The period of time occupied by such treatment, before the blood serum of the horse is considered of value. for treatment of cases of diphtheria, varies with each horse. Indeed, many horses may be given such treatment without the production of antitoxic properties in their blood serum, sufficiently strong to be of any value. Moreover it is at present impossible to tell beforehand whether a horse will give strong antitoxic serum or not.

With the hope of finding method or means of foretelling the result of the injection of horses with toxin, experimental work was carried on in this laboratory under the direction of Dr. B. Meade Bolton, Director of the Labora

tory, until November 1, 1896. (Journal of Experimental Medicine, Vol. 1.) It was thought that possibly some horses might have antitoxin normally present in their blood, which would influence the result of the treatment. It was found that certain horses did possess antitoxic properties in their blood, but subsequent observation failed to show that such normal antitoxin affected the result of our work on those horses. Equally good and quite as poor results were obtained from both horses with, and horses without, such normal antitoxin.

January 1, 1896, there were nine horses under treatment. In May two died suddenly, from overdoses of toxin. The serum of one of these two was of sufficient antitoxic strength to be of value. The other horse's serum was of no value so far as antitoxin was concerned. Two horses were discarded, in December, after eighteen months fruitless treatment.

Of the remaining five, three have produced serum containing 100 to 150 units of antitoxin to each cubic centimeter or slightly superior to the ordinary standard antitoxin. The serums produced by the other two horses contain between 60 and 80 units per cubic centimeter, and has not been used on cases of diphtheria. Three horses have been received during the year, but none of them produced a strong antitoxic serum.

In March, the laboratory began to regularly supply the Municipal Hospital with diphtheria antitoxin of standard strength. Shortly afterward the medical profession and the general public were notified that diphtheria antitoxin could be obtained on application at the laboratory, provided the physician obtaining it would signify that it was to be used on a patient unable to pay for it, and also that he would report the result to the laboratory.

Physicians applying for antitoxin are requested to fill out and sign the proper application:

APPLICATION FOR ANTITOXIN.

Physician using the Antitoxin.......

Residence.........

Patient's name.........

Residence........

Date..........

Is the antitoxin to be used for treatment or protection?...........

(over)

This is to certify that the antitoxin is to be used on a patient who is unable to purchase Antitoxin, and the result will be reported on the proper blank form to the Laboratory.

Signed............

TO BE FILLED OUT AT THE LABORATORY.

Description of the Antitoxin supplied........

Lab. No. of the Antitoxin.........

Quantity and strength............

He is then given the amount he has applied for, each bottle of which is labelled, with the amount of serum it contains and its antitoxic value.

Every bottle is enclosed in a neat, round paste-board box, which also contains a blank form for reporting the result of the use of the remedy.

RESULTS OF THE INOCULATION OF ANTITOXIN.

Date........

Name of the physician using the Antitoxin.......

Residence.......

Patient's name.....

Residence................

(over)