216 Veterinary Medicine. 



phile cells of the blood are presumabl} ? important factors as the 

 natural sources of the leucomains. The spleen as the seat of im- 

 portant blood changes and as preeminently the seat of election of 

 internal anthrax is probably involved. The dogs from which 

 Bardach had removed the spleen were found to be three times as 

 susceptible to anthrax as were the dogs that had not been ope- 

 rated on. Leo's rats, in which he had produced mellituria b)' the 

 administration of phloridzin were found to be much more suscep- 

 tible to anthrax. The liver is also a favorite seat of election of 

 internal anthrax. The products of the healthy liver, are probably 

 in some measure protective. 



No matter where the defensive products are formed, the prac- 

 tical problem is to secure their production without imperilling life. 



By Minimum Dose. Chauveau and Colin secured this in the 

 larger animals by intravenous injection of a minimum dose,— one 

 or two bacilli. This is more lasting in effect if a second and 

 stronger dose is injected some days later. 



By Weakened Virus. This has been secured by heating the 

 defibrinated blood to 55 C. for ten minutes (Toussaint); Pasteur, 

 Chamberland and Roux accomplished the same end by making 

 anthrax cultures at 42 to 43 C. in presence of air ; Chauveau by 

 subjecting the virulent culture for eight days to oxygen under a 

 pressure of 8 atmospheres at a temperature of 38 C; Chamber- 

 laud, Roux and others have cultivated the bacillus in weak 

 antiseptic bouillons as phenic acid (1:600 or 1200), bichromate of 

 potash (1:2000 or 5000), sulphuric acid (2:100). 



Other methods have been followed, as growing the bacillus in 

 the blood or serum of immune animals (dog, chicken, pigeon, 

 white rat, frog). 



Of these different methods that of Pasteur has been most ex- 

 tensively adopted. The temperature of culture (42 C.) prevents 

 the formation of spores and the duration of exposure to air 

 gradually lessens the virulence until in 12 or 13 days it is not 

 fatal to the Guinea pig and after 31 days it fails to kill the young 

 mouse. Thus preparations of varying grades of virulence, and 

 adapted to the varying susceptibility of different animals, are 

 secured. The protective inoculation is made by preference in 

 spring, when there is less chance of complication by a coincident 

 accidental infection, it is to be avoided if possible in animals at 



