its Pathology and Methods of Protective Inoculation. 293 



Secondary Fever. 



Animals which are " salted " are liable to subsequent attacks of 

 fever which have no necessary relation to fresh infection. I have 

 observed numerous cases of this description among the " salted " 

 animals under my observation and during periods when the sickness 

 was unknown. 



Symptoms of the Disease. 



It occurs under two forms the Dikkopziekte* and the Dunpaarde- 

 ziekte.f In the former the head and neck swells up enormously, thus 

 affording trustworthy indications of illness during life. In the latter 

 form, as a rule, no symptoms appear until close to the period of death, 

 when the animal becomes subject to very rapid breathing with heaving 

 at the flanks. At the moment of death, in both forms, it is common to 

 find a huge cloud of white foam ejected from the mouth and nose. 

 This foam is produced from a free exudation of blood plasma into the 

 air passages. 



Owing to the fact that the animals suffering from the Dunpaarde- 

 ziekte show no symptoms until toward the end of the period of illness, 

 it had come to be believed that the whole period of the disease was 

 limited to a few hours' duration. 



Post-mortem Phenomena. 



The pericardium is almost invariably filled with a yellow fluid 

 which, while usually clear, is sometimes blood-stained. Solidified 

 gelatinous exudate is frequently found in relation to the beginning of 

 the aorta. The pleural cavity is frequently occupied by yellow fluid, 

 and the interlobular and sub-pleural tissues are also frequently dis- 

 tended by this material. The interlobular tissue is frequently so dis- 

 tended by exudation that the lung tissue proper is dissected up in all 

 directions. The subcutaneous tissue, especially about the great vessels 

 in the neck, is commonly found to be invaded by this exudation, while 

 in the Dikkopziekte the swelling of the head and neck is due to this 

 effusion. 



The yellow fluid of the pericardium and the pleurae is spontaneously 

 coagulable in the presence of minute traces of blood. 



These represent the more characteristic pathological conditions 

 obtaining in this disease, among which one characteristic is most 

 noticeable by its absence, e.g., inflammatory phenomena. Pathological 



* Dikkopziekte, a Dutch word signifying "thick-head sickness," is applied to 

 the form in which the swollen head is the most obvious symptom. 



f Dunpaardeziekte, " thin horse-sickness," applied to the form in which the head 

 is little or not at all swollen. 



