THE CANINE PASTEURELLA 457 



The equine pasteurella often passes unnoticed while the micro-organisms 

 of the secondary infection especially in cases of strangles and contagious 

 pneumonia are found in large numbers. 



Cultures are only obtainable with difficulty direct from the tissues of 

 the horse. To recover the organism from 

 suspected material it is best to inoculate a I 



guinea-pig intra-peritoneally and then to sow .-.+ f , \ " 



cultures with the peritoneal fluid of the guinea- f ~ 

 pig, but even then it is often impossible to ^ . V** 



recover the organism. :/ " * 1* , 



The equine bacillus kills guinea-pigs and uv^V--* 

 rabbits and sometimes horses on sub-cutaneous * . 

 inoculation. Horses succumb to intra-venous ..-,'*' Z ~ . 



inoculation. It is only slightly pathogenic for ^ * ^ 



fowls and pigeons and these birds only succumb V-.' * .- +. 



after intra-venous inoculation of one or several 



cubic centimetres of the peritoneal exudate of Fm ^.-Pa^ureiu equi. Film 

 an infected guinea-pig. Rats and oxen are from the peritoneal exudate of a 

 immune guinea-pig carbol-thionin. 



Morphologically the organism differs in no way from the other members 

 of the group. 



8. PASTEURELLA CAN IS. 



(The bacillus of distemper.) 



Distemper, which attacks chiefly young animals and assumes very various 

 forms (typhoid fever, dog-plague, dog-pox, infectious pneumonia, gastro- 

 enteritis etc.), [has been attributed] to a pasteurella (Lignieres, Phisalix). 

 Distemper in the cat is due to the same organism (Lignieres). 



Phisalix investigated a septicsemic condition in guinea-pigs accompanied by the 

 lesions of pneumonia. He found it to be due to a small bacillus having all the 

 morphological and cultural features of a typical pasteurella and pathogenic for 

 rabbits, mice, pigeons and dogs. Phisalix considered that his bacillus was identical 

 with that which Lignieres later described in distemper in dogs. 



The micro-organism of distemper is somewhat difficult to isolate from the 

 tissues of the dog : it can only be found in the acute forms, and is most 

 easily recovered from the blood stream, but secondary infections rapidly 

 supervene with the result that the pasteurella disappears. 



Carre diluted the nasal secretions with sterile water and after filtering the 

 emulsion through a very porous bougie obtained a filtrate, sterile on cultiva- 

 tion but capable of infecting fresh animals. From these experiments it may 

 be concluded that the true virus of distemper is an invisible micro-organism, 

 the pasteurella being present merely as a secondary infection. It may be 

 necessary to review the aetiology of " distemper," since it is possible that 

 some of the clinical conditions known by this name are due to a pasteurella 

 others to a filtrable virus (Chap. LXIV.) [and see also M'Gowan's bacillus, 

 infra]. 



Experimental inoculation. The dog pasteurella is only slightly virulent 

 for animals other than the dog and cat. 



It kills mice and guinea-pigs on intra-peritoneal inoculation with the 

 lesions of acute peritonitis. Post mortem, the intestine, liver, kidneys and 

 spleen are congested : the organism can be recovered from the blood and is 

 also present in large numbers in the peritoneal exudate. 



Rabbits succumb to intra-peritoneal inoculation : intra-venous and sub- 

 cutaneous inoculation is also fatal if a very large dose of the virus be given, 



