GANGRENOUS CORYZA. 323 



.^r ^''' T'" "''"' "''■™^' disturbance assume the form of 

 epileptiform convulsions, and it is possible that the paraplegia referred 

 to simply marks the last stage of the disease. ' ^ ^ 



Causation. The essential cause of gangrenous coryza has not yet 

 been dehnitely ascertained. Within recent years teachers of the highest 

 authority have represented the disease as a general affection belonginc^to 

 the hfemorrhagic forms of septicemia (Nocard and Leclainche). Nocard 

 has found ovoid bacteria in the false membranes of the larynx and 

 Leclainche a paracoli-bacillus in the mesenteric ganglia and the intes- 

 tines, but the disease has never been reproduced in a characteristic and 

 complete form similar to the clinical type. 



Other microbes have also been described as occurring in the blood or 

 discharges ; but attempts to transmit the disease by using cultures or the 

 different morbid products which observers have collected have invariably 

 failed, and it has therefore been concluded that the disease is not 

 contagious, but merely infectious. 



Moussu does not regard this disease as a hemorrhagic septicemia, 

 because the blood proves sterile unless grave pulmonary, intestinal or 

 renal complications occur, and because the disease appears capable of 

 being cured in a short time by simple methods. In the present state of 

 knowledge he prefers to regard it as an infectious disease of diphtheritic 

 form, at first localised in the upper respiratory and digestive tracts, 

 always tending towards a grave toxemia, and towards complications due 

 to various other infections. 



Even though direct contagion has not been proved, it is impossible 

 to doubt that stables may become infected. This is sufficiently proved 

 by the continued appearance of the disease when disinfection is neglected 

 after the occurrence, of the first case. 



It is possible that the causes formerly assigned — viz., chills, the 

 influence of draughts, and a morbid predisposition — may increase sus- 

 ceptibihty in animals otherwise well cared for, but it is quite certain 

 that infection of the stable is an important factor. 



Lesions. The lesions vary with the complications, but those shown 

 in the beginning are always identical. The mucous membrane of the 

 nasal cavities is congested, inflamed, sphacelated, and ulcerated at dif- 

 ferent points. The turbinated bones and the ethmoid cells may become 

 necrotic ; in the larj'iix the region of the glottis is always most markedly 

 affected ; the mucous membrane becomes ulcerated in the neighbourhood 

 of the vocal cords, and the tissues may become more deeply attacked. 

 In the trachea and bronchi the mucous membrane undergoes desqua- 

 mation, and may become ulcerated at the points where false membranes 

 have formed. The mucous membrane of the sinuses is always affected, 

 but is rarely ulcerated. 



Y 2 



