170 G. G. Heslop: 



with a similar result. In glucose Martin's broth there is a very 

 definite acid reaction developed. The acid reaction is apparent 

 after the third day of incubation, and increases towards the 

 eighth day, when it apparently attains its maximum, though it 

 is apparent throughout the life of the culture. No gas is de- 

 veloped by the organism in this medium. In maltose Martin's- 

 broth there is also a very definite acid reaction produced by the 

 organism, but no gas is developed. In lactose Martin's broth,, 

 and in saccharose Martin's broth, there is growth of the organ- 

 ism, but no acid or gas is developed. Tubes of each medium not 

 inoculated, were incubated as controls, and showed an unaltered 

 appearance on comparison with tubes of similar media, uninocu- 

 lated, and not incubated. The reaction of the organism on cul- 

 tivation in media containing various sugars can be summarised' 

 as follows : — 



Saccharose. Glucose. Maltose. Lactose. Mannite. Dulcite. 



Acid - — - ++ - + - — - No growth - No growth- 

 Oas . — ._-_. — . t 



+ + Strongly acid. 



In order to obtain cultures it is an absolute rule that the- 

 culture medium must contain serum. In ordinary broth the or- 

 ganism will not develop. On ordinary nutrient agar the organ- 

 ism will not develop. No growth takes place on gelatine. For 

 all growths obtained, Martin's peptone bouillon has been used 

 as a basis for the medium, and various sera have been tried in 

 various proportions. Growths have been obtained in Martin's 

 broth, to which either ox serum, horse serum, or rabbit's serum 

 has been added. No growths have been obtained in Martin's- 

 broth with guinea-pig's serum added, although several such tubes- 

 have been inoculated. Growths have been obtained in Martin's 

 broth medium, in which the added ox serum did not exceed 

 3 per cent. It was found that about the most satisfactory serum 

 content for the culture medium was 7.5 per cent., although very 

 satisfactory growths could be obtained with slightly greater or 

 lesser amounts of serum in the medium. 



Filtration Experiments. 



Experiments were made to test the filter passing properties-, 

 of the organism of contagious pleuro-pneumonia. Virus obtained 

 from active lesions in the lungs of cattle, affected with contagious, 

 pleuro-pneumonia naturally acquired, which were slaughtered at 

 the City and other Metropolitan Abattoirs, was mixed in varying: 



