256 Veterinary Medicine. 



fection. It is to be avoided in animals at hard work, in advanced 

 gestation, in full milk, in extreme youth or in ill health. To 

 secure the best results it should be repeated with a stronger pre- 

 paration 10 or 15 days after the first injection. The acquired 

 immunity lasts a year or over and is probably perpetuated by 

 new and nonfatal doses taken in casually on the anthrax pastures. 

 Hundreds of thousands of live stock in all parts of the world 

 have been treated in this way with the result of reducing a mor- 

 tality of 2, 5 or 10 per cent, to insignificant proportions. It can 

 only be safely adopted on anthrax lands, as elsewhere it ftay lead 

 to the stocking of new areas with a malignant germ which in 

 young and susceptible animals reacquires its original virulence. 



It can never be saiely ignored that we are dealing with the 

 living seed of a most deadly infection. Though robbed of a 

 large part of its virulence by artificial culture at 107.5° F., yet 

 many accidental conditions contribute to a relapse to its original 

 potency, and when it has once killed a victim the renewed vir- 

 ulence is usually persistent. If the virus, employed for protec- 

 tive purposes in cattle and sheep, is inoculated on Guinea pigs of 

 I to 30 days old, from these to those of several months, and from 

 these last on sheep, the virulence is constantly and persistently 

 enhanced. The same is true of the microbe which is inoculated 

 on a succession of pullets of steadily encreasing ages (Roux and 

 Chamberland) , or on a succession of pigeons (Metchnikoff) . The 

 germs reinforced in potency in any such way are liable to be the 

 starting points for dangerous infections in animals and permanent 

 contamination of soils and waters. Fortunately an occurrence 

 of this kind is rare, yet with a wide application of the Pasteur«an 

 inoculation the opportunities are great, and with the free sale 

 and distribution of the enfeebled anthrax ' ' vaccin ' ' , the evil 

 may grow indefinitely. The method departs from the ideal one, 

 which aims at a final extinction of the disease, and accepts in 

 place a more temporary protection of the generation which makes 

 up the herd or flock at a given time., with no consideration for 

 the generations that are to come after. Eradication of anthrax 

 cannot always be secured, yet every effort should be made to 

 attain it, and above all to check its infection of new land. 



Technique. The weakened virus (ist "vaccin") is sold in 

 tubes holding enough for 100, 200 or 300 sheep. Of this ^th 



