220 VETERINARY BACTERIOLOGY 



rarely, enters the blood. Metastatic involvement of the lungs 

 and other organs occurs in a few cases. 



Immunity. No true toxins have been demonstrated; endo- 

 toxins are probably produced, and released through the autolytic 

 disintegration of the organism. Agglutinins are developed in 

 sufficient quantity, so that the blood of a patient frequently ag- 

 glutinates in a dilution of 1 : 50. Although no distinct bacterio- 

 lysins have been demonstrated, specific amboceptors for the organ- 

 ism may be shown to be present in the blood by the hemolytic 

 absorption of complement test. Opsonins probably play the 

 largest part in the .development of immunity. All these anti- 

 bodies mentioned have been determined to be present in the 

 serum of immunized horses. 



Vaccination against the disease is not practised. Flexner 

 and Jobling have prepared an immune serum from the horse by 

 the injection of dead bacteria, followed by the injection of living 

 bacteria and the products of their autolytic digestion. The 

 serum is injected directly into the spinal canal after the withdrawal 

 of an equal amount of the purulent exudate. It comes in direct 

 contact, therefore, with the organisms, and probably stimulates 

 phagocytosis by its opsonin content. The use of this serum has 

 proved highly successful; by its means mortality has been mate- 

 rially reduced. 



Bacteriologic Diagnosis. Lumbar puncture, with demonstra- 

 tion in smears of a gram-negative diplococcus, occurring prin- 

 cipally within the leukocytes, constitutes a satisfactory diagnosis. 

 The agglutination test may be applied, but is not used in practice. 



Transmission and Prophylaxis. How the organism gains en- 

 trance to the spinal and brain cavities is not certainly known. It 

 is found in the early stages of the disease upon the nasal mucous 

 membranes. It is spread probably by the use of infected hand- 

 kerchiefs or by the inhalation of infectious droplets. 



Micrococcos intracellularis eqoi 



Synonym. Diplococcus intracellularis equi. 



An organism in no important particular differing from the 

 meningococcus has been reported by Johne, Ostertag, and others 

 in epizootic or cerebrospinal meningitis in horses. Ostertag 



