(Diphtheria Antitoxin.)

Definition. - A fluid separated from the coagulated blood of a horse immunized through the inoculation of diphtheric toxin (U. S. P.). The German Pharmacopoeia recognizes also the dried serum.

Antidiphtheric serum gradually loses its power, the loss in one year varying between 10 and 30 per cent. " The standard of strength, expressed in units of antitoxic power, should be that approved or established by the U. S. Public Health and Marine-Hospital Service" (U. S. P.). All manufacturers selling diphtheria antitoxin in the District of Columbia, or in States other than the one in which it is manufactured, must secure a license issued by the Secretary of the Treasury, on recommendation of the Surgeon-General of the Public Health and Marine-Hospital Service.

Dose. - Average dose: 3000 units. Immunizing dose for well persons, 500 units (U. S. P.).

The serum has now been made official in the U. S. Pharmacopoeia.

Caution. - Should be kept in sealed glass containers in a dark place at temperatures between 4.50 and 150 C. (400 and 590 F.).

From a careful consideration of the subject in its relations to diptheria, we may safely conclude:

1. That immunized serum forms a remedy which experience proves to be wholly innocuous and eminently adapted for use in human infection.

2. That antidiphtheritic serum has in every respect corresponded with the most sanguine hopes of its advocates, its employment being attended with astonishing success wherever properly used and in sufficient quantities.

3. Finally, that it is incontrovertibly established that by means of injecting serum temporary immunity from infection may be readily conferred, permanent protection being contingent merely upon a renewal of treatment.

The present status of diphtheria antitoxin may be presented in a few words. It has established itself as a specific in the treatment of this disease. During the past year the use of larger doses has become more general, and it seems certain that better results are obtained. The administrators of the Chicago Department of Health give 2000 units in all cases of suspected diphtheria, and employ 1000 units as an immunizing dose. During the months of November and December this department treated 219 cases of bacteriologically proved diphtheria, all charity cases, with a death-rate of 4.1 per cent. Some two and a half years ago, when antitoxin was not used, the death-rate from diphtheria treated by this department was about 35 per cent.

Tuberculosis. - It may be stated, in general terms, that the. microbic nature of tuberculosis was admitted by nearly all writers upon the subject before the discovery of the pathogenic microorganism. Villemin in 1866 had established by experiment the infectious character of the malady; but in France the idea seemed almost revolutionary, creating no enthusiasm, it being reserved for Germany, through the indefatigable labors of Robert Koch, to develop and elucidate the theory conceived by Villemin. Koch discovered the bacillus of tuberculosis, and even succeeded in isolating and cultivating it, the pure cultures obtained by him always producing tuberculosis in every form. His original communication, addressed to the Physiological Society of Berlin, bore date of April 10, 1882, and at once stimulated experimental research in others, who fully confirmed his discovery.

Various methods of inoculation have been adopted in tuberculosis: 1, Inoculating the patient with another disease; 2, inoculation with attenuated tuberculosis or that proceeding from a different species, as from birds; 3, inoculation of the soluble bacillar products - tuberculin; 4, injection of blood taken from animals often immune against tuberculosis; 5, injection of serum drawn from inoculated animals; 6, finally, injection of serum taken from immunized animals. With the last two of these methods we are properly concerned. The fifth has been scientifically adopted by Babes, Richard, and Hericourt, who have treated a large number of cases in which various cures have been effected. The main obstacle of the procedure lies in the difficulty of successful inoculation, the greater part of the animals employed dying of infectious nephritis.

By the sixth method, as employed by Bernheim, this fatality is largely obviated, a careful procedure with the serum of immunized animals proving the most efficacious hitherto devised. The process of immunizing consists in injecting the toxic products normally secreted by Koch's bacillus, and is, in effect, that adopted by Behring in preparing the antitoxin of diphtheria. In experimenting upon a large number of animals, suffice it to say that the results obtained by Bernheim were eminently satisfactory, every case indicating improvement, and the actual cures being about 40 per cent. So convinced was he of the sovereign value of his method that he emphatically declared it to be the only rational procedure possible in tuberculosis. Within recent years Magliano and Behring have announced important advances in the serum or vaccine treatment of tuberculosis.

It is difficult to sum up in a few words the present status of the serum treatment of tuberculosis. We are not in the possession of any true antibodies that are of service in the direct treatment of patients suffering from tuberculosis, but there are excellent reasons for believing that an immunizing serum or vaccine is a possibility in the not-far-distant future.

Pneumonia. - Inoculations of attenuated virus readily confer immunity in lower animals, reduction of virulent germs be attained by the use of desiccated pneumonic viscera. The saliva of a patient, collected after defervescence, ensures protection to the mouse, the same being true of blood-serum. Immunization of animals was inaugurated by Emmerich and Fovitsky in 1891, subsequent investigators confirming their experiments under varying conditions, Foa and Scabia finally employing human serum in the inoculation of rabbits with marked success.