The Contagion, Insidious and Tenacious. 59 



among us for tliirty-four years, and in spite of all obsta- 

 cles has made a slow but constant extension, is sufficient 

 irround for the gravest apprehensions. A disease-poison 

 which shows such an obstinate vitality and such persist- 

 ent aggressiveness cannot be allowed to exist among us 

 without the certainty of future losses which will eclipse 

 tliobe of Great Britain by as much as our herds of cattle 

 exceed those of that nation. A recent outbreak in Clin- 

 ton, N. J., caused by a cow brought from Ohio, suggests 

 the possibility of the disease having already reached the 

 latter State, an occurrence which was inevitable sooner or 

 later, but the actual existence of which must enormously 

 increase our dangers. With every such step westward 

 there is the introduction of more diseased and infected 

 cattle into the natural current of the traffic, and the ear- 

 lier probability of the general infection of all parts to the 

 east of such ultimate centres of disease. There is, 

 fiu'ther, the infection of more cattle cars which, carried 

 west, may be the means of securing a rapid extension of 

 the plague to our most distant States and Territories. 



"Eelative Dangers of the Poisons of Lung Fevee and 

 OTHER Plagues. 



" The persistent vitality of the lung-fever poison, in com- 

 parison with that of any other animal plagues, is note- 

 worthy. It has held a tenacious grasp on the United 

 States for over a third of a century, though forbidden by 

 circumstances to make a wide extension. Aphthous fever 

 (foot and mouth disease), on the other hand, though 

 twice imported into Canada within the last ten years, and 

 on one occasion widely spread in New Tork and New 

 England, was on each occasion easily and early extin- 

 guished, and with little or no effort on the part of the 

 States. It might indeed almost be said to have died out 

 of itself. Even the dreaded rinderpest has its poison 

 early destroyed by free exposure to the air, in thin lay- 

 ers, at the ordinary summer temperature. Numerous ex- 

 periments on hides hung up and freely exposed in warm 

 weather, have shown that the infecting power is lost as 

 s(jon as they are quite dried. But the poison of lung 

 lever maintains its virulence for months in the dry state 



