280 CONTAGIOUS DISEASES. 



products of animals which have died of anthrax. In one re- 

 markalile outbreak which came immediately under my notice, 

 the disease appeared amongst sucking calves of the pure short- 

 horn breed, and which had never partaken of other food than 

 what they obtained by sucking, the dams remaining healthy. 

 Anthrax is also disseminated through the agency of flies, and 

 Bolliu'^'-er, who has observed that the disease is often most 

 prevalent when flies are in the greatest abundance, has induced 

 it in rabbits by inoculating them with flies caught on the car- 

 cases of animals dead from anthrax. The flies, however, resist 

 the influence of the virus, although bacteridse are found in them. 

 Pasteur's assertion that the spores of anthrax are brought to the 

 surface of the ground by earth-worms — contested by Koch — is 

 now confirmed by Bollinger, who has found that five per cent, of 

 the worms coming irom an infected pasture-ground contained the 

 spores of anthrax. 



Dogs, cats, white mice, and Algerian sheep are said to have 

 an immunity from the disease. — (Crookshank). 



In opposition to the view of the spontaneous origin of anthrax, 

 we have the observations of many eminent pathologists — and this 

 view is now almost universally accepted — who maintain that the 

 malady is due to the propagation of a now well-known aerobic or- 

 ganism, 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 hdtonnets, and which were believed to be products of 

 putrefaction, and that anthrax was a septicaemia or putrefaction 

 of the blood. These Idtonncts were afterwards observed in 

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

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

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



aqueous humor he mixed the smallest 

 speck of a liquid containing the 

 rods, placed it under the microscope, 

 warmed it suitably, and watched the 

 subsequent action. During the first 

 two hours hardly any change was 

 Fig. ii.-Transparent rods. noticeable, but at the end of that 

 period the rods began to lengthen, and the action was so rapid 



