ANTHRAX 315 



blood, and give rise to general poisoning without abscess formation ; 

 in pycemia, however, multiple abscesses occur in various parts of the 

 body, including internal organs. Prom the results of experiment it is 

 now believed that suppuration in any form or degree is invariably 

 the result of bacterial infection. But it is not known in what way 

 bacteria exactly cause the condition ; it may be due to extracellular 

 toxins, or intracellular poisons, or to the bodies themselves setting up 

 primary irritation, or to all three conditions. Positive chemiotaxis is 

 probably the explanation of the immigration of the leucocytes. 



Anthrax 



This disease was one of the first in which the causal agency of 

 bacteria was proved. In 1849 Pollender found an innumerable 

 number of small rods in the blood of animals suffering from anthrax. 

 In 1863 Davaine described these, and attributed the disease to them. 

 But it was not till 1876 that Koch finally settled the matter by 

 isolating the bacilli iu pure culture and describing their biological 

 characters. 



It is owing in part to its interesting bacterial history, which 

 opened up so much new ground in this comparatively new science, 

 that anthrax has assumed such an important place in pathology. 

 But for other reasons, too, it claims attention. It appears to have 

 been known in the time of Moses, and was perhaps the disease 

 described by Homer in the First Book of the Iliad. Eome was 

 visited by it in 740 B.C. 



Anthrax is an acute disease, affecting sheep, cattle, horses, goats, 

 deer, and man. Cats, white rats, and Algerian sheep are immune. 

 Swine become infected by feeding on the offal of diseased cattle 

 (Crookshank). 



Clinical Characters. — In most instances the first intimation of an outbreak of 

 anthrax is the discovery of a dead animal in the pasture or byre. The animal may 

 have been left a few hours earlier in apparent good health ; at least, there may have 

 been nothing to attract attention, or give warning of the near approach of death. 

 Occasionally there are, however, premonitory symptoms of an attack of anthrax 

 which can be recognised by an expert. The affected animal is dull, and disinclined 

 to move. If the case occurs in a herd at pasture the fact is sometimes indicated by 

 the separation of the sick animal from the rest. The affected animal will occasionally 

 cease to feed, and stand with its head bent towards the ground, and sometimes a 

 little blood is discharged from the nostrils and also with the faeces. Close attention 

 will enable the observer to detect an occasional shiver and trembling of the limbs, 

 which passes rapidly over the body, and then ceases. The shivering fits may then 

 become more frequent, and perhaps, while these signs are being noted, the animal 

 wUl suddenly roll over on its side, and, after a few violent struggles, expire. On 

 close inspection, especially in the case of swine, it will often be found that there is a 

 good deal of swelling under the throat extending down the neck ; and the swollen 

 part will at first be hot and tender to the touch, but as the disease progresses 

 it becomes insensitive and cold. 



