302 ANTHRAX. 



ture. In order to make them again capable of sporing it 

 is necessary to adopt special measures, such as passage 

 through the bodies of a series of susceptible animals. 



Anthrax spores have extremely high powers of resistance. 

 In a dry condition they will remain viable for a year or more. 

 Koch found they resisted boiling for five minutes ; and dry 

 heat at 140 C. must be applied for several hours to kill 

 them with certainty. Unlike the bacilli, they can resist the 

 action of the gastric juice for a long period of time. They are 

 often used as test objects by which the action of germicides 

 is judged. For this purpose an emulsion is made by scrap- 

 ing off a surface culture and rubbing it up in a little sterile 

 water. Into this sterile silk threads are dipped, which, after 

 being dried over strong sulphuric acid in a dessicator, can 

 be kept for long periods of time in an unchanged condition. 

 For use they are placed in the germicidal solution for the 

 desired time, then washed with water to remove the last 

 traces of the reagent and laid on the surface of agar or 

 placed in bouillon, in order that if death has not occurred 

 growth may be observed. 



Anthrax in Animals. Anthrax occurs from time to 

 time epidemically in sheep, cattle, and, more rarely, in 

 horses and deer. These epidemics are found in various 

 parts of the world, although they are naturally most far- 

 reaching where legal precautions to prevent the spread of 

 infection are non-existent. All the countries of Europe are 

 from time to time visited by the disease, but in some it is 

 much more common than in others. In Britain the death- 

 rate is small, but in France the annual mortality among 

 sheep was probably i o per cent of the total number in the 

 country, and among cattle 5 per cent. These figures, how- 

 ever, have been largely modified by the system of preven- 

 tive treatment which will be presently described. In sheep 

 and cattle the disease is specially virulent. An animal may 

 suddenly drop down, with symptoms of collapse, quickening 

 of pulse and respiration, and dyspnoea, and death may occur 

 in a few minutes. In less acute cases the animal is appar- 

 ently out of sorts, and does not feed ; its pulse and respira- 



