Serum against the Epithelioma or Diphtheria of Birds 



by 



Concerned for more than ten years 

 with the study of various diseases, caustd 

 by filterable germs, of more special in- 

 terest to veterinary medicine, I became 

 convinced that these germs form a quite 

 horao,i;eneous group, the important cha- 

 racters of which are to be found in the 

 conditions of parasitism and may be 

 considered in a synthetical manner in 

 the following way: 



lo. All filterable germs arc obligatory 

 parasites, that is may only manifest vi- 

 tal activity when inside a host, although 

 able to remain, in a state of latent life, 

 outside the organism. The cultures, which 

 may sometimes be obtained in special 

 culture media, are short-lived and the- 

 refore are not to be found amongst the 

 collections of the most prominent insti- 

 tutes of research however complete they 

 may be. 



2o. They are very exacting as to the 

 choice of their host: hog cholera is ex- 

 clusively confined to porcines, foot-and- 

 mouth disease can be transmitted easily 

 only to artiodactyla, and contagious epi- 

 Ihelioma even presents difficulties with 



regard to its transmission from one spe- 

 cies of birds to another. 



3o. In the cases were they are not 

 observed lo be so particular (rabies, cow- 

 pox etc.) the germs are more liable to 

 undergo mutations: innis fixe, vaccines, 

 etc. The race thus obtained has vaccina- 

 ting properties, and no other method for 

 obtaining vaccines can be applied, seein^j 

 that the methods used for attenuating 

 bacteria usually prove very unsatisfac- 

 torj' in this case. 



4°. The morbid symptoms which 

 they cause are usually intensified 

 by association with bacteria generally 

 of small pathogenic activity: for instance 

 a paratyphus bacillus or a pasteurella 

 plays a role in the pulmonar or intesti- 

 nal form of hog-cholera (swine-plague); 

 in pox a streptococcus, in the epithelio- 

 thelioma of birds a staphylococcus, and 

 so forth. 



5". The attack the organism .sufTers, 

 when it does not prove fatal, causes 

 immunity, at times of a very lasting 

 kind, as in pox, epithelioma of birds, 

 velloNv fever, etc., at others oí very short 



