Pleuro- Pneumonia of Cattle. 167 



It was to be expected that, following on the isolation and suc- 

 cessful cultivation of the causal organism of contagious pleuro- 

 pneumonia, attempts would be made to apply the usual serological 

 reactions, such as agglutination, precipitation, and complement 

 fixation, for the diagnosis of the disease in the living animal. 



Dujardin-Beaumetz (1900) (6), after experiments with cul- 

 ture and serum from immunised bovines, announced that the 

 " serum of hyper-vaccinated animals is not bactericidal, and ag- 

 glutination is not able to be of any use in the diagnosis of pleuro- 

 pneumonia." However, in 1906 (7) he found that massive in- 

 travenous injections of pure culture in Martin's broth plus horse 

 serum into horses gave rise to agglutinins in the horse serum r 

 which could be demonstrated in dilutions up to 1-50. Further 

 he demonstrated that this same serum would give a precipitin re- 

 action when combined with the serum of experimentally inocu- 

 lated bovines, and he suggested that, although as a serodiagnostic 

 method it was delicate in performance, it might be of some use 

 in order to confirm clinical diagnosis m certain chronic cases o£ 

 the disease. 



Schochowsky in 1912 (18) published the results of his work 

 on complement fixation in relation to pleuro-pneumonia. He 

 concluded that it was impossible to obtain a reliable complement 

 fixation reaction, and that complement fixation had no value as 

 a serodiagnostic method for contagious pleuro-pneumonia. This 

 view was also expressed, though not so definitely, by Poppe 

 (1913) {17), who obtained unsatisfactory and contradictory re- 

 sults with his work on complement fixation. He found, how- 

 ever, that a precipitation test (Fornet's ring reaction), gave 

 fairly reliable results, but that sera had to be specially selected 

 to act as precipitinogen. He. concluded that the test could be 

 used with advantage for the diagnosis of doubtful cases where 

 the clinical evidence was insufficient. 



K. F. Meyer (1914) (10), in a review of the filterable viruses 

 in general, refers briefly to the more important work which has- 

 been done in recent years on contagious pleuro-pneumonia. He 

 points out that " the study of the filterable viruses is attended 

 with considerable technical difficulties, and the experimental re- 

 sults obtained depend largely on the ingenuity of the experi- 

 menter." 7 Referring to the complement fixation test in pleuro- 

 pneumonia, he states : — " In some unpublished experiments the . 

 author found the complement fixation tests very- unreliable for 



7. P. 267. 



