398 ACTINOMYCETES. 



2. Mixed infection with streptococci and diphtheria 

 bacilli is more dangerous for the animal than pure diph- 

 theria infection. 



Nevertheless the diphtheria bacillus alone may undoubt- 

 edly produce all the clinical symptoms of sepsis (Gener- 

 sich). 



(d) In animals : Certain spontaneous disease produced 

 by Loffler's bacillus has never been observed in any ani- 

 mal. The susceptible guinea-pig is immune to the diph- 

 theria bacillus introduced by feeding, by inhalation, or 

 by swabbing. Spontaneous disease (diphtheric broncho- 

 pneumonia) is said to occur in cats (E. Klein, C. B. vin, 

 7). Klein claims also to have observed spontaneous diph- 

 theria in milk cows, in which, moreover, the diphtheria 

 bacilli escaped in the milk. 



The spontaneous diphtherias of hens, pigeons, 1 and 

 calves always (?) have other causes. (Compare Lofner, 

 Mitt. G. A. n; Ritter, H. R., 1896, 839). 



Still, certain of the causes of "animal diphtheria " 

 appear to be transferred to man. Consult the well-known 

 observation of Gerhard (II. Kong. f. innere Med.), and 

 also Galli-Valerio (C. B. v xxn, 500: extensive critical 

 review of literature). 



Experimental Observations Regarding Pathogenic 

 Effects. — (a) Upon animals: The virulence of freshly iso- 

 lated cultures varies greatly; in general, severe cases fur- 

 nish virulent cultures and mild ones cultures with slight 

 virulence; still, there are exceptions. Experimental and 

 accidental (cultural) attenuation is often observed. Roux 

 and Yersin assert that there occurs a regular, striking re- 

 duction of virulence in the last few diphtheria bacilli 

 demonstrable during convalescence. It was not found so 

 by Escherich, and still other writers cultivated virulent 

 bacilli from convalescents long after the clinical symptoms 

 disappeared. A good standard for the virulence of a cul- 



1 Gallez claims to have positively demonstrated in Belgium that, 

 besides the " fowl diphtheria," which has nothing to do with human 

 diphtheria, there is also a " fowl glanders," which is caused by attenu- 

 ated Loffler's bacilli (H. K., 1896, vi, 472). 



