330 



BACILLI PATHOGENIC IN ANIMALS. 



that, as in the case of the calves, the infiltration was 

 occasioned by the long bacilli. Further proof of the 

 etiological r6le of these bacilli must be furnished by 

 more extensive cultivation experiments. 



Group of 

 bacteria 

 which set up 

 gastro- 

 enteritis. 



Earlier experi 

 ments with 

 mixtures of 

 bacteria. 



Later experi- 

 ments with 

 pure cultiva- 

 tions. 



Another group of bacteria characterised by similarity 

 in their pathogenic action is formed by those bacilli 

 which set up a more or less severe gastro-enteritis in 

 the animals ordinarily employed for experiments, such 

 as dogs, rabbits, and guinea-pigs, the disease occurring 

 when the bacteria are injected in relatively large numbers, 

 either into the veins, or subcutaneously. Similar symp- 

 toms were formerly often obtained experimentally by 

 the employment of mixtures of bacteria, and Virchow* 

 observed, as long ago as 1847, vomiting and diarrhoea 

 with ultimate collapse, in animals after injection of a 

 fluid obtained from putrid fibrin. Among more recent 

 writers we need only mention Popoff,f who obtained 

 similar results by the injection of a mixture of yeast, 

 and also of putrid Pasteur's solution; and Blumberg,J 

 who worked with putrefying dog's blood, and with 

 the water employed for the maceration of dog's flesh, 

 and set up violent vomiting and rapid death after intra- 

 venous injection, and milder and less constant symptoms 

 after injection subcutaneously. On post-mortem ex- 

 amination of the animals, the severe cases showed the 

 appearances of a hsemorrhagic gastro-enteritis with 

 marked swelling, and often deep ulceration of Peyer's 

 patches. In milder cases there was only hyper aemia of 

 the stomach and intestines, and swelling of the follicles. 



After the elaboration of the methods for the pure 

 cultivation of organisms, experiments have been made 

 with different species of bacteria, and cultivations 

 of these bacteria have set up the same morbid 

 symptoms and the same anatomical appearances after 

 intravenous, and sometimes after subcutaneous in- 

 jection, as was done by the mixtures formerly employed. 



* Handb. der spec. PathoL u. Therapie, vol. i., p. 242. 

 f Berl. klin. Woch., 1872, Nr. 43. 

 t Virch. Arch., vol. 100, p. 377. 



