In sealed flasks they keep unaltered for an indefinite period 

 of time. 



(4) The blood is drawn out with a sterilized pipette from 

 the heart of the animal recently dying of anthrax. With the 

 microscope it must be ascertained that it was anthrax. Then 

 the animal is carefully dissected, so as not to puncture the 

 heart. A piece of strongly heated glass is rubbed on the part 

 of the heart to be punctured with the pipette, and then the 

 pipette, is put in and the blood sucked into it. This blood is 

 sown in chicken broth to cultivate the bacilli. After three 

 days it is seen whether it has altered, or whether the culture 

 obtained is of pure bacillus anthracis. This can be judged 

 by the naked eye by gently inclining the flasks and seeing 

 against a light whether the culture is filamentous and sunk in 

 the clear broth. Every flask, whether of broth, of virulent virus, 

 or of vaccine, must be daily examined to see if any of the 

 disturbing organisms have been growing in them. They can 

 be easily detected with the naked eye if the flasks are held 

 against a light, but in any case of doubt the microscope must 

 be used. The usual disturbing organisms are (i) the points 

 doubles or diplococci, which give the broth or vaccine a dull 

 troubled appearance, and when more than one day old a 

 white deposit settles on the bottom of the flask; (2) penicil- 

 lium and aspergilius fungi, which float on the top in lumps ; 



(3) bacillus subtilis, which produces a veil or film on the top ; 



(4) trainees, which form white lines sticking to the sides of 

 the glass as rays ; and (5) bacterium termo, which also troubles 

 the clear liquid, and, looked at through the microscope, appear 

 as minute corkscrew shaped rapidly moving vibrions, smaller 

 than bacillus anthracis. At every stage, therefore, it is ne- 

 cessary to be careful that any other organism than bacillus 

 anthracis is not being cultivated as bacillus anthracis. 

 When the blood sown in the chicken broth has been three 

 days in the Etuve Pasteur, it has to be particularly seen that it 

 has given rise to a culture of bacillus anthracis only in the flasks. 



