Petechial Fever. 143 



destroyed the cervical sympathetic ganglion, when there super- 

 vened marked exudation, lasting for three days. The complete 

 blocking of veins by pressure or aseptic ligature, does not pro- 

 duce a spreading oedema, whereas in ordinary suppurative phlebi- 

 tis, with abundance of toxins in the tissues this is a constant result. 



The toxin theory does not fully account for those cases that 

 occur suddenly, without any manifest pre-existing disease, and 

 as the result apparently of cold and chill. On the other hand, 

 it is only a very small proportion of horses exposed to the same 

 degree of cold and chill that contract petechial fever, and it might 

 well be surmised that in these few an unknown focus of suppura- 

 tion or other lesion existed prior to the chill or that toxins having 

 the requisite devitalizing and vaso-dilating properties had been 

 absorbed from fermentations in the bowels or elsewhere. The 

 mere exposure is harmless to the very great majority of subjects. 



In any case it must be accepted that the debility and impaired 

 local innervation, nutrition and function, that attend on the expos- 

 ure to cold and toxins must be looked on as potent contributing 

 causes. The predilection of the swellings for dependent parts 

 (limbs, venter, face) shows the influence of gravitation and con- 

 gestion. Whether there is present any special microbe which 

 has yet eluded discovery, but which is the main pathogenic 

 factor, must be left to the future to decide. 



In cases that appear to be due to cold or chill alone, the disease 

 is held to be primary ; in those following on another affection, 

 secondary. 



Among the diseases on which petechial fever supervenes as a 

 secondary affection contagious inflammatory affections of the 

 lungs and air passages hold a bad preeminence. Strangles, in- 

 fluenza and contagious pneumonia, about in the order named, 

 are especially causative factors or occasions of petechial fever. 

 Among the other affections on which it supervenes may be named 

 pharyngitis, abscess of the nasal sinuses, hepatic, renal and other 

 internal abscesses, acute coryza, laryngitis, or bronchitis, enteritis, 

 abortion, aggravated grease suppurating wounds of the skin, 

 abrasions by harness, suppurating sores after firing, infective 

 arthritis with open joint, amputation of the tail, and castration. 



Lesions. In certain cases these may be largely confined to pe- 

 techiae and slight blood extravasations, which are distributed 



