Contagious Fleuro-Pneuvionia of Cattle. 183 



Experiments have accordingly been made with mannite and 

 •dulcite (Gurr), using adequate controls, and it has been found 

 that growth of the organism occurs in both mannite and dulcite 

 Martin's broth, but no acid or gas is developed in the medium 

 as a result of the growth which takes place. Andrade's indicator 

 has been used as the indicator for the experiments. The mannite 

 and dulcite were added to the broth media in the proportion of 

 2 per cent, in each case. Growth was apparent in from four to 

 iive days after incubation at 37° C. 



The fermentation reactions of the organism of contagious 

 pleuro-pneumonia are therefore as follow: — 



Sa(icharose Glucose Maltose Lactose Mannite Dulcite 



Acid -_.++- + ._-_._ 

 Gas - - - - ._._._._ 



(jJrowth takes place with each reagent. 

 + = Acid. + + = Stron<^ly acid. - = No reaction. 



Complement Fixation. 



Attempts have been made to simplify the technique for the 

 •complement fixation test, but it has been found that with each 

 attempted modification of the technique already laid down fur- 

 ther inaccuracies have occurred in the results. As a result of 

 the further experiments carried out it is now apparent that the 

 best results with the complement fixation test are obtained when 

 the technique set out in detail in the writer's previous article is 

 ■carefully followed. 



Various new preparations have been tested as antigens for 

 the complement fixation test. Certain of the preparations tested 

 have shown some ability to fix complement in the presence of a 

 positive serum, while with others no visible fixation of comple- 

 ment has occurred at all. In all cases the new preparations tested 

 liave been proved to be inferior in antigenic value to the alcoholic 

 ex.tract of subepidermal tumour tissue used in the experiments 

 reported fully in the writer's previous article. 



The new preparations tested as antigens were as follow : — 



Antigen i. — An alcoholic extract of the dried residue after 

 rapid evaporation of a seven days' old culture of the organism 

 of contagious pleuro-pneumonia in Martin's broth ox serum. 

 On testing, this extract was found to possess no demonstrable 

 antigenic value. 



