n THU complete POVLTRt iOOK. 



precUble interval in the impregnation, the whole series will reproduce the atten- 

 nated virulence of that which served as the starting point. SunUarly, when the 

 virulence is small, it produces no effect." , . , ... 



Professor Pasteur proceeds to show that this decrease of virulence in the 

 disease-germ is due to continued exposure to the oxygen of the air, and that it 

 may be continued to such a point as shaU cause the>accination of the fowl with 

 it to produce more or less complete immunity from subsequent attacks, and yet 

 cause little or no inconvenience to the fowl itself. H the virus be very much 

 weakened it may require several vaccinations to give complete immunity— three 

 or four being found necessary in some of PSsteur's experiments, and the opera- 

 tion may require to be repeated at intervals of a year. This discovery is yet in 

 its infancy, but it is worthy of extended and careful investigation. 



FrmeniAon by breedmg from mmeceptMe fowls.— 'Dr. Salmon states that he has 

 found a considerable number of fowls that were capable of Resisting repeated 

 inoculations with very active virus, some showing only the mildest symptoms of 



Fig. 27. 



the disease, and others remaining entirely free from, any appreciable results, 

 either in general health or at the point of inoculation, and Chauveau has shown 

 that the Algerian sheep are, as a breed, insusceptible to the influence of charbon, 

 hence they urge the importance of breeding from such animals, with the hope 

 of producing strains that will possess this characteristie in a stiU greater degree. 

 If there is reason to fear that the flock has been or is likely to be exposed to 

 the contagium of fowl cholera we should advise the use of hyposulphite of soda 

 in their drinking water, at the rate of an ounce to the pailful of water. If the 

 yellow coloration of the urates appear before a fowl shows other signs of 

 disease the use of the homeopathic preparation of strychnine called JV«a! Vomi- 

 ca three may be of service, five or six peUets to be given to a large fowl once a 

 day, and a smaller number to a smaller fowl. This remedy has given good re- 

 sults with UB, when used in time. Dr. S. J. Parker writes to the Cotmtry Gen- 

 tleirum that he has found Eucalyptus globvMs very serviceable at this period of 

 the disease, by relieving the indigestion which is among the earliest symptoms. 

 Ten drops of the strong tincture are given with four grains of salt and half a 

 teaspoonfnl of ground cayenne nenner in a teasnoonful of water. 



