124 COMMON DISEASES. 



sponsible for the conveyance of dried anthrax spores. Insects, 

 after feeding upon infected blood and tissues, may transmit the 

 virus to healthy animals through fresh wounds or sores, or by 

 puncturing the skin. Insects may probably, also, infect food 

 materials in troughs and mangers, by conveying virulent matter 

 on their bodies and feet. Carrion birds, through the medium 

 of their excrement, or soiled feet, may infect pastures on which 

 they alight. 



Carnivorous and omnivorous animals, as dogs and hogs, 

 running at large, after feeding upon anthrax carcasses, may carry 

 away virulent blood on their feet ; and, if these animals die them- 

 selves, they become fresh centers of the disease. 



Food-stuffs, as pastures, and commercial feeding materials 

 such as the cereal grains and their by-products, hay, etc., raised 

 upon lands infected with anthrax spores, may carry those spores 

 and spread the disease. 



Human beings coming in contact with virulent anthrax ma- 

 terial, and having their clothes, shoes, hands, etc., soiled thereby, 

 may easily spread the disease. 



Neglect to properly dispose of anthrax carcasses is, perhaps, 

 the factor most responsible for the continuance and spread of 

 anthrax. 



Period of incubation. — The time that elapses between in- 

 fection and symptoms, depends upon the method of infection, and 

 amount of infective material introduced, and may range from a 

 very few hours to several days. 



Symptoms. 



Puhiionary anthrax. — This form is probably not of frequent 

 occurrence in the lower animals. Dried spores may. however, 

 be inhaled from infected hay, whole or crushed grains, etc. 

 There are: suddenness of attack; elevation of temperature, 104 

 to 108 F. ; inappetence; difficult respiration; injection of visible 

 mucous membranes; discharge of blood from respiratorv tract; 

 unsteady action of the heart ; small and frequent pulse ; stagger- 

 ing movements; convlusions, and death resulting from asphyxia. 

 This form is confined chiefly to the herbivora. 



External or cutaneous anthrax. — There is swelling at point 

 or points of inoculation (carbuncle or malignant pustule), with 



