296 ANTHRAX. 



now the first part to give rise to symptoms. In all these 

 forms of the affection in the human subject, the bacilli are 

 in their distribution much more restricted to the local 

 lesions than is the case in the ox, their growth and spread 

 being attended by inflammatory oedema and often by 

 haemorrhages. 



Historical Summary. Historical researches leave little doubt that 

 from the earliest times anthrax has occurred among cattle. For a long 

 time its pathology was not understood, and it went by many names. 

 During the early part of the present century much attention was paid 

 to it, and, with a view to finding out its nature and means of spread, 

 various conditions attaching to its occurrence, such as those of soil and 

 weather, were exhaustively studied. Pollender in 1849 pointed out 

 that the blood of anthrax animals contained numerous rod-shaped 

 bodies which he conjectured had some causal connection with the 

 disease. In 1863 Davaine announced that they were bacteria, and 

 originated the name bacillus anthratis. He stated that unless 

 blood used in inoculation experiments on animals contained them, 

 death did not ensue. Though this conclusion was disputed, still by 

 the work of Davaine and others the causal relationship of the bacilli 

 to the disease had been nearly established when the work of Koch 

 appeared in 1876. This constituted that observer's first contribu- 

 tion to bacteriology, and did much to clear up the whole subject. 

 Koch confirmed Davaine's view that the bodies were bacteria. He 

 observed in the blood of anthrax animals the appearance of division, 

 and from this deduced that multiplication took place in the tissues. 

 He observed them under the microscope dividing outside the body, 

 and noticed spore formation taking place. He also isolated the bacilli 

 in pure culture outside the body, and by inoculating animals with them, 

 produced the disease artificially. In his earlier experiments he failed 

 to produce death by feeding susceptible animals both with bacilli and 

 spores, and as the intestinal tract was, in his view, the natural path of 

 infection, he considered as incomplete the proof of this method of the 

 spontaneous occurrence of anthrax in herds of animals. Koch's ob- 

 servations were, shortly afterwards, confirmed in the main by Pasteur, 

 though controversy arose between them on certain minor points. 

 Moreover, further research showed that the disease could be produced 

 in animals by feeding them with spores, and thus the way in which the 

 disease might spread naturally was explained. 



The Bacillus Anthracis. Anthrax as a disease in man 

 is of comparative rarity. Not only, however, is the 

 bacillus anthracis easy of growth and recognition, but in its 

 growth it illustrates many of the general morphological 



