142 CONTAGIOUS DISEASES OK DOMESTICATED ANIMALS. 



ou the other hand, held that the iiou-appearauce of this disease in his- 

 toric time, in any country in which it had not previously existed, 

 unless in cases where its introduction could be clearly traced to the im- 

 portation of a diseased animal or its products, and its continued absence 

 from all countries into which no such importation had been made im. 

 plied, unequivocally, that the assumed cases of spontaneity were also 

 cases of infection, tliough investigation had failed to show the precise 

 channel by which the germs had been introduced. A comparison of 

 the nationalities of the advocates of spontaneity and against it is very 

 instructive as showing that the believers in spontaneity are those whose 

 experience has been gained at the termini of the cattle traffic from 

 Central and Eastern Europe, at points (Belgium, France), in short, where 

 the infection of lung plague is being constantlj' imported, and from 

 which it is never entirely absent, whereas the disbelievers in spontaneity 

 are mainly from countries (England, Sweden, Switzerland, Roumania, 

 America, &c.), in which lung plague has been stamped out, or into which 

 it has been first introduced in recent times by a well-attested importa- 

 tion of disease, and v.here its area of prevalence is sharply limited to 

 places infected through such importations. 



This well illustrates the predominating influence of the immediate 

 surroundings. Had the able advocates of spontaneity lived in Spain 

 or Portugal, where herds abound, but to which the lung plague has 

 never penetrated, or in Scandinavia, where its occasional importations 

 have been as persistently stamped out ; or in Switzerland, the imme- 

 morial home of the plague, but from which it has been expelled; or in 

 England, which it respected until it was imported in 1839 and where 

 it has prevailed ever since, but still spares the exclusively breeding 

 districts; or in the United States, where it was imported in 1848 and 

 ]851>, and where it was effectually stamped out in the fenced farms of 

 New England but continues to prevail through the constant changes 

 and successive infections in the city dairies of the Middle Atlantic 

 States, and finally where the whole West and South maintains a per- 

 fect immunity ; or in South Africa or Australasia, where the disease 

 long unknown, has spread from single importations and from the con- 

 stant mingling of herds maintains an universal i)revaleuce ; or, finally, 

 in Canada, Newfoundland, Mexico, or South America, to which the 

 plague has not yet been iniported and where, as in the exclusively 

 breeding districts of infected countries, no spontaneous case has ever 

 occurred to start it on its desolating career, they would have realized 

 that they were advocating a mere phantom danger and that the plague 

 which has failed to appear in historic time in a country not already in. 

 I'ected from without may safely be trusted not to appear in the future 

 with such exotic contagion. They would no more argue from the first 

 case of the plague than the botanist would argue from the first oak that 

 oaks must now appear without seed or slips j they would accept the 

 unvarying testimony from all parts of the inhabited earth which are 



