INTRODUCTION XV 



of property in a year, it is not difficult to see the value of that 

 precise knowledge which is required to deal promptly and 

 efficiently with these plagues. 



It is a narrow and incorrect view to hold that the farmer 

 who owns these animals is the only one who suffers from the 

 ravages of the diseases which destroy them. Animal pro- 

 ducts constitute a large part of the national food supply. If 

 this food supply is diminished, made dearer and more difficult 

 to obtain, want, misery, disease and death among mankind 

 increase. At first the effects of a scarcity of the food supply 

 may be almost inappreciable and felt only by the ver}- poor; 

 but as the conditions of famine are approached, suffering is 

 multiplied and intensified until whole communities are pros- 

 trated or destroyed. An abundant supply of wholesome and 

 nutritious food is therefore an essential condition of the wel- 

 fare and prosperity of the people. 



The great commercial operations of nations also depend 

 to a great extent upon the good condition of animals. When 

 all of the horses are disabled by an epizootic, as they have 

 been on rare occasions by influenza, the delivery of purchased 

 goods has nearly ceased, the shipments of flour, iron, machin- 

 ery and other products have been temporarily arrested and 

 business has been almost at a standstill. Again, it should be 

 remembered that we export annually from the United States 

 forty million dollars worth of live animals, one hundred mil- 

 lion dollars worth of meats, fifty-five million dollars worth of 

 lard, tallow and other animal fats, and nine million dollars 

 worth of dairy products. Let this traffic be stopped by the 

 shortage of supplies or by prohibitive orders of other nations 

 on account of the unrestrained prevalence of infectious dis- 

 eases, and the earnings of steamships, and railroads, and 

 banks, and commission houses, are at once diminished; men 



