When actual obstructive dyspnoea begins the question of operative interference comes into consideration. For the details of intubation and tracheotomy the reader is referred to works on surgery. It seems that intubation should be our first choice, and it should be done as soon as slight cyanosis appears.

Serum-therapy-The growth of the Klebs-Loeffler bacillus (Plate 10) in the body-tissues develops the peculiar toxalbumin to the poisoning from which the constitutional symptoms are due. Nature in some unknown way elaborates in the body an antidotal poison, the antitoxine, and when the two poisons balance in effect the constitutional symptoms cease and the patient recovers. If antitoxine can be made outside the body, and injected when needed, in sufficient doses, without waiting for the system to elaborate it, the disease, it was thought, might be stamped out at the onset. The growing experiences of the past year tend more and more to prove the correctness of this assumption.

The method by which the antitoxine is obtained is as follows: All animals susceptible to diphtheria can be rendered immune by injecting into their bodies pure cultures of the bacillus in gradually increasing virulence. Weakening of the toxine is effected by diluting it with iodine solutions. For various reasons the horse is the most satisfac tory animal for the purpose.

When immunized, the blood-serum contains a large quantity of antitoxine and can be used for subcutaneous injections in human diphtheria. A small quantity of tricresol is added to the serum to keep it from decomposing. Three reliable serums are in the market-Roux's, Behring's, and Aronson's. Each serum supplies a weaker (“immunization serum") and a stronger solution.

The dose of antitoxic serum varies with the size and the weight of the patient, the virulence of the disease, and the

all the cases together, the mortality has been reduced onehalf, and with improved methods and improved appreciation of the value of early diagnosis and early treatment the mortality will still further be reduced.

ERYSIPELAS.

Definition.-Erysipelas is an infectious inflammation of the skin with constitutional symptoms, caused by the inoculation of the streptococcus erysipelatosus.

Etiology. The disease is due to infection of the lymphatics of the skin by a streptococcus which is identical in appearance with the streptococcus pyogenes. Infection always occurs through wounds or abraded surfaces, intact skin and mucous membranes affording absolute protection. Two forms are usually described-(a) a traumatic form complicating surgical wounds and injuries, and (b) an idiopathic form occurring usually in the face, in which no traumatic point of origin can be found. The only real difference between these two forms is that in the one the point of entrance is apparent, while in the other it is slight and is usually overlooked. The disease is favored by poor hygiene, by bad plumbing, and by contact with infected cases. As inoculation through abraded surfaces is necessary to cause the disease, it cannot be considered as contagious in the ordinary acceptation of the term. It is commonest in alcoholic and debilitated patients and in those suffering from Bright's disease. One attack does not secure immunity. Some patients are exceedingly susceptible and may suffer from repeated attacks.

Pathology.-Erysipelas is really a progressive lymphangitis of the skin involving the perilymphatic tissues by continuity. There is an infiltration of the cutis vera by fibrin serum and leucocytes; this infiltration in severe cases may extend to the subcutaneous connective tissue. The

lymphatics are crowded with the streptococci, especially at the margin of the patch and extending into the healthy skin. Vesicles and bullæ may be formed. Suppuration does not occur unless there be an added infection by pus microbes.

Symptoms begin from fifteen to sixteen hours after inoculation.

General Symptoms.-The disease usually is initiated by at chill and a rise of temperature to 103° or 104° F. or even higher. Nausea and vomiting are common at the onset. The pulse is full and bounding, and is rarely over 100 except in the most severe forms or in debilitated and alcoholic subjects. In these cases the pulse may become rapid and feeble and may be a source of real danger.

Delirium belongs to the severer cases, and is especially marked in alcoholic patients. It may be either mild and maniacal or low and muttering. There is usually severe headache, especially in erysipelas of the face and scalp. Prostration is marked in proportion to the severity of the disease. There may be albuminuria. In fatal cases the patient may pass into a "typhoid condition."

The constitutional symptoms may be mild, such as would be due to a slight local inflammation, or they may be exceedingly well developed, resembling those caused by any severe general infection.

Local Symptoms.-The skin becomes swollen and shiny and of a rose color which disappears on pressure. It is distinctly thickened and indurated. The patient complains of feelings of tension, burning, and itching. The swelling is most marked in places where there is considerable loose connective tissue, as in the face or the eyelids, and in these localities there is also considerable cedema. Inflammatory changes are more marked at the border of the eruption, which is abrupt and elevated and shows tongue-like pro

longations projecting into the healthy skin. These characteristics of the border of the patch are distinctive and absolutely diagnostic. In some cases there appear vesicles or bullæ.

If there be an added infection by the ordinary pus microbes, the contents of the vesicles or the bullæ may become purulent, or there may be complicating phlegmonous inflammation of the deeper structures of the skin, or metastatic abscesses of internal viscera, or septic inflammation of any of the serous membranes. In some cases the local inflammation is so intense that superficial gangrene results. Exfoliation of the skin usually follows the subsidence of the eruption.

When the disease once begins, it is common for it to spread from the periphery, so that large surface areas may become successively involved. Its progress may be checked by any decided fold in the skin, particularly the naso-labial fold. It is frequently limited at the border of the hairy scalp. In facial erysipelas the chin and the anterior aspect of the neck are never affected. In some cases erysipelas shows a tendency to creep from place to place, subsiding in the old situations while new areas are constantly becoming invaded. In this way it may spread over most of the body and the extremities. This form is often described as "erysipelas migrans." In other cases the erysipelatous inflammation may attack a part far separated from the primary seat of infection. This condition may result either from infective embolism or by auto-inoculation, the cocci being carried from the primary site and being inoculated through a scratch or an abrasion into the distant part. These cases are designated "metastatic erysipelas."

If the streptococci obtain entrance to the lymphatics of the post-partum uterus, the most virulent and fatal form. of puerperal sepsis results.