DISEASES OF THE BLOOd! 151 



and plenty, extreme cold and almost tropical heat, being 

 peculiarly combined on the wide grassy expanses of the 

 steppes. Thus, the animals there become much predis- 

 posed to this as well as other disorders, but we must 

 coincide with the opinion at which Professor Unterberger 

 has arrived, that eveu here the disease does not originate 

 spontaneously. From this enzootic centre the disease is 

 carried along the great traffic roads towards Western 

 Europe, and follows the course of armies in the field. 

 Thus, as trade facilities increase the disorder will be 

 liable to spread to a greater distance in a shorter time ; also 

 .certain definite rinderpest routes from Central Russia might 

 be noted ; also times of war prove times of pestilence, a 

 fact which has long been observed. Meat food for troops 

 in Central, Eastern, and Western Europe must be drawn 

 from the large supplies of Eastern Russia, and in the 

 hurry of the transport and the commissariat duties vete- 

 rinary inspection is too often neglected. 



Nothing is really known about cattle plague contagium. 

 It is said to diffuse through the air to the distance 

 of 500 yards (Gerlach, 40 metres; Hayne, 30 to 1000 

 metres), bringing about infection of other stock, but 

 most observers are inclined to consider the latter esti- 

 mate must be taken to apply to mediate contagion 

 rather than true infection. The discharges may retain 

 their power of communicating the disorder for eleven 

 months (Jessen), three months (Camper and Viedazyr), 

 six years (Weiss and Hering). In the latter cases it was 

 retained in capillary tubes, or between two pieces of glass, 

 and hence not exposed to the air. So we can bring to 

 bear weighty arguments against the theory of spontaneous 

 origin of this disorder ; any statement that it may occur 

 as a result of ordinary causes must not be admitted. 

 Practically, all efforts must be directed against the con- 

 tagium which already exists. This may be conveyed by 

 an unaffected animal, by hides of affected ones, by at- 

 tendants, &c; and the persistence of the virus renders 

 disinfection, and, where possible, destruction of things 

 which have been in contact with any diseased animal 



