148 ANTHRAX AND ANTHRACOID DISEASES. 



giving it with the food upon which the animal is fed. When 

 blood is so altered, it tends to accumulate in the vessels of the 

 soft structures of the body, such as the areolar tissue, spleen, 

 enteric mucous membrane, and lungs, where it rapidly transudes 

 through the walls of the altered and debilitated blood-vessels, 

 and constitutes the various local manifestations of a septic fever. 

 In opposition to the view of the spontaneous origin of 

 anthrax, we have the observations of many eminent pathologists, 

 who maintain that the malady is due to the propagation of a 

 now well-known organism, the Bacillus anthracis, the history 

 of which is as follows : — 



These organisms were first observed by Brauell, and afterwards 

 by Delafond and Gruby, in the blood of animals which had 

 died of anthrax, as peculiar staff-shaped bodies, which Delafond 

 designated bdtonnets, and which were believed to be products of 

 putrefaction, and that anthrax was a septicaemia or putrefaction 

 of the blood. These bdtonnets were afterwards observed in 

 1850 by MM. Davaine and Rayer, and some time later Koch 

 studied them, and found the aqueous humour of the ox's eye to 

 be particularly suitable for their nutrition. With a drop of the 



aqueous humour he mixed the smallest 

 speck of a liquid containing the rods, 

 Ci*^ placed it under the microscope, warmed 

 1',^^ it suitably, and watched the subsequent 

 action. During the first two hours 

 ;jj(ii\,,,^rii= hardly any change was noticeable, but 



^' at the end of that period the rods began 



Fig. 1. -Transparent rods. ^^ lengthen, and the action was so rapid 



that at the end of three or four hours they had attained from 

 twenty to thirty times their original length, and at the end of 

 a few additional hours had formed filaments in many cases a 

 hundred times the length of the original rods; and further it was 

 seen that within the transparent rods little dots appeared; these 



Fig. 2. — Spore-bearing filaments. Fig. 3. — Spores. 



became more and more distinct, until the whole organism was 

 studded with minute ovoid bodies, like peas within their shell. 

 After a time the integument fell to pieces, the place of each rod 



