Schütz, Hill, Pilz and a number of others have sought artificial immunity, by the injection of blood serum from a horse that has recently recovered from the malady. The results were very contradictory. In some cases the disease came to a sudden end. In other stables no new cases appeared either in those treated with serum or in those left without treatment. In other experiments, new cases occurred among those treated with the serum;—in Weishaupt’s cases after a lapse of one or two months. This is exactly what might be expected. If the horse supplying the blood serum had really recovered, and if the microbes (streptococci) had disappeared from the blood, the latter would of necessity retain little of the toxins, but much more of the antitoxins, the active production of which would be continued by the stimulated leucocytes. These antitoxins would neutralize the toxins, in case of invasion and prevent that from reaching the maximum of intensity that it would otherwise have reached, but would be powerless to stimulate the leucocytes of the inoculated animal into the habit of themselves producing antitoxins. This would act rather as a curative than a prophylactic agent, and its value would be spent as soon as the injected antitoxins were eliminated from the system.
The true line of inquiry would have been, whether injection of the toxins, which acting on the leucocytes would have stimulated these to the habit of producing antitoxins in large amount, might not be expected to give an immunity as lasting as that which follows on a casual attack of the disease. Lignieres appears to have approximated to this, in his experiments on mice and rabbits. In horses suffering from contagious pneumonia it lowered the temperature, but did not materially affect the result of the attack. If we adhere to Lignieres’ own theory of causation by cocco-bacillus and later by streptococcus or some other complicating infection, we can scarcely hope that the toxins of the streptococcus or other complicating microbe will immunize against the cocco-bacillus or mutually against each other. If complete protection is aimed at, the toxins of his cocco-bacillus, and of Schütz’s streptococcus, and of any other possible microbe which may produce a secondary complication, ought to be employed.
At the date of this writing no satisfactory sero-therapy for this disease has been worked out and publicly demonstrated.
INFECTIOUS STABLE BRONCHITIS. SCALMA.
Definition. An infectious inflammation, of the upper air passages and bronchia, attended by high fever, special nervous irritability and a protracted convalescence.
Dieckerhoff gave the name scalma (rogue) to outbreaks in given stables of an infection, showing the high temperature of brustseuche, (104° to 107° F.) a similar incubation (6 to 7 days), a correspondingly tardy extension from animal to animal, and duration of the disease. The apparent differences are in the absence of the profound dulness, the yellowness of the mucosæ, and the yellow or rusty nasal discharge, in the ready response to the voice or touch, the disposition to bite or kick, the spasms of the larynx and sudden dyspnœa, in certain cases, and the paroxysmal cough in others. Apart from these transient respiratory troubles the pulse and breathing are unaffected, relatively to the elevation of temperature. Sometimes the jaws are kept in constant motion, from nervousness or pharyngeal trouble.
In the absence of any conclusive bacteriological investigation, it may be surmised that this is a form of brustseuche which has not advanced to the same grade of destruction of red globules and prostration of the nerve centres, the latter showing only an excited and irritable condition.
Treatment and prevention do not differ materially from what is required in contagious pneumonia. The irritable cough may be soothed by inhalations of warm water vapor, with alcohol, camphor, eucalyptol, or opium, or electuaries of bromides, belladonna or stramonium, and local derivatives to the throat.
Most cases are mild and recover in a week, the cough lasting for two weeks more.