INFECTION. 121 



or inoculation. The cells become accustomed to the material in- 

 troduced in such small quantities, or it becomes so changed that it 

 is robbed of sufficient of its deleterious characteristics, so that, while 

 accustoming themselves to its action, they are still able to overcome 

 it in the struggle for existence. 



The continual infection of the human race with syphilitic germs 

 for centuries has hardened the cells of the organism, so that they 

 can better resist their attacks on exposure to infection. In the nat- 

 ural world, this acquired adaptability to circumstances exerts such 

 an influence as to become strongly hereditary : may it not be so, 

 in a less degree, with regard to some diseases ? There seems to be 

 no other reasonable hypothesis by which we can explain both the 

 natural and acquired immunity which the animal species possess 

 against certain forms of infectious diseases and poisons. 



Summed up : Either the cells are strong enough to win in this 

 struggle for life ; or, in the struggle, they become, as it were, accus- 

 tomed to such influences, and are no more open to the attacks of the 

 germs ; or they are overcome in the struggle, and the autositic or 

 infected organism dies. 



Anthrax in Man. 

 Pustula Maligna, Carbunculus Contagiosa. 



The fact that this disease is transmissible to human beings should 

 be known to every one. On account of the liability to infection of 

 those having the care of anthrax-diseased animals, it is essential that 

 the veterinarian, as well as the public, should have some knowledge 

 of its deportment in the human organism. 



Until recent years the disease has been looked upon by most 

 medical writers as belonging exclusively to the surgical branch of 

 medicine. 



That the disease occurs in human beings was known to very 

 early medical writers. 



Etiology. 



The idiopathic or spontaneous eruption of the disease must be 

 strongly contradicted, especially as we have conclusively shown that 

 such is not the case among animals. 



There are no sufficient proofs that show that the disease ever 

 occurs in man, except by direct inoculation from diseased animals, 

 or their products. 



Medical writings do not give any evidence that the disease ever 

 occurs among human beings from the mere residence in notorious 

 anthrax districts. 



