36 Th^ Farmer's Veterinary Adviser. 



violence when conditions are favorable. As a field of wheat 

 suffers alike in quantity and quality from poor soil and lack 

 of cultivation, manure, rain, sunshine, and heat, but in spite 

 of all brings to maturity a seed for a future crop, so the 

 plague-germ languishes somewhat when the animal systems 

 and their surroundings do not favor its propagation, yet it 

 does not perish, but from the mild case it advances to tlie 

 more severe and deadly whenever the circumstances become 

 more favorable. As an instance of the obstinate vitality of 

 the disease-germ, we see that in an uninterrupted open-air 

 life, in a land of perpetual summer, the limg-plague of cattle 

 advanced more rapidly, proved more deadly, and defied 

 human control more successfully on the grassy plains of 

 Australia and South Africa than in any other part of the 

 globe. 



No measure less radical than the destraction of every dis- 

 eased animal and its infecting products will furnish a 

 guarantee of the permanent extinction of plagues spread by 

 living vegetable germs only, but in all such plagues the de- 

 struction of the germ gives a perfect assurance of this re- 

 sult, and is the bounden duty of the Government. 



PEOPAGATION OF DISEASE-GEEMS OUTSIDE THE ANIMAL BODY. 



The absolute destruction of disease-germs and the extinc- 

 tion of the corresponding plagues is limited by the fact that 

 the germs of certain maladies live and increase out of the 

 animal body. Prominent among these may be named the 

 germs of anthrax, typhoid fever, yellow fever, and cholera, 

 which increase not only in numbers, but often in deadliness 

 as well, in sewers, cesspools, dung-heaps, filth-saturated 

 soils, and undrained impervious ground which is rich in de- 

 composing organic matter. "Where a germ of a given plague 

 is permanently domiciled in a soil favoi'able to its preserva- 

 tion and growth it is manifest that the disposal of sick ani- 



