258 TEXT-BOOK OF BACTERIOLOGY, 



at all — i.e., only local effects are produced and the original virulence 

 has almost disappeared. It may be imagmed that this diminution 

 of virulence is sometimes a source of embarrassment to us, for it 

 is by no means easy always to obtain thoroughly efficient and reli- 

 able material at the moment it is wanted. 



This behavior of the glanders bacillus, however, supplies a clear 

 proof that ■ it does not find outside the bodies of animals the condi- 

 tions which completely suit its requirements and enable it to de- 

 velop its qualities fully. It is a genuine parasite, and when forced 

 to exist under circumstances foreign to its nature and habits, pro- 

 tests against such treatment, as we have seen. 



We have not yet succeeded, by the use of high temperature or 

 otherwise, in producing an artificial attenuation of the glanders 

 bacilli. On the other hand, we have seen that a sort of artificial 

 strengthening has been obtained by H. Leo, who transmitted, the 

 glanders to white mice (which are naturally non-susceptible) by 

 feeding them with phloridzin and so making them diabetic. 



By microscopic investigation, by cultivation, and bj' the results 

 of transmission we know that glanders is caused by a specific 

 micro-organism. We must here always consider in all cases what 

 relations the symptoms of the disease bear to their exciting cause, 

 how the peculiarities of the former are to be explained in connec- 

 tion with the properties of the latter, and, above all else, how the 

 bacillus gains entrance into the body, and how it causes the develop- 

 ment and spread of the disease. 



Our experiments have shown that the glanders bacilli are able 

 to enter by way of the subcutaneous cellular tissue after slight in- 

 juries to the skin; and it seems that this is a frequent source of 

 infection under ordinary circumstances. In human beings in par- 

 ticular the virus generally enters at some scratch or slight wound 

 which has come in contact with it. Thus the disease almost ex- 

 clusively attacks persons whose occupation brings them into close 

 contact with horses, such as coachmen, stable-boys, farmers, sol- 

 diers, etc. First, pustules and abscesses appear in the immediate 

 neighborhood of the inoculation wound, and it is not until later 

 that swellings of the joints, ulcers on the mucous membranes, and 

 the other s3'mptoms of a severe affection make their appearance. 



In horses, in addition to this source of affection, there is no 

 doubt that the disease is also frequently transmitted by the breath. 

 It is much to be desired that suitable experiments should en- 

 lighten us as to the conditions under which this kind of infection 

 takes place. For the present we only know its symptoms, which, 

 however, are generally very significant. As a rule, the nasal cavity 



