ANTIGENIC STRUCTURE 613 



These findings are in agreement with those of other authors, except with regard 

 to peptonization, which is less commonly reported. 



The proteolytic activity of staphylococci is not very strong. Some strains are 

 fibrinolytic (Saski and Fejgin 1937, Neter 1937), and some, particularly those of 

 canine origin, can digest coagulated horse serum (Minett 1936). Lipase production 

 has been reported by Orcutt and Howe (1922) and Christie and Graydon (1940). 

 Most aureus strains produce hyaluronidase. 



The methyl-red test is generally positive with the aureits and albus strains, 

 negative with the citreus strains. The Voges-Proskauer reaction is given by most 

 strains of Staphylococcus aureus. According to Winslow, Rothberg, and Parsons 

 (1920), most strains of staphylococci reduce nitrates to nitrites. Hucker (1924a), 

 on the contrary, found that, though 49 out of 50 aureus strains reduced nitrates, 

 only 23 out of 152 albus strains were able to do so. Hydrogen sulphide is stated by 

 Andre wes and Gordon (1905-6) to be formed in small quantity by the pyogenic 

 staphylococci, in greater quantity by Staphylococcus albus. We have been unable 

 to confirm this. Ammotvia is produced by 89 per cent, of the golden and white 

 strains (Winslow et al. 1920). /wcZo^e is apparently never produced (Hucker 1924a). 



Antigenic Structure. — -Studying agglutination of staphylococci by immune 

 rabbits' sera, the early workers (Kolle and Otto 1902, Otto 1903, Proscher 1903, 

 Kutscher and Konrich 1904, Veiel 1904, Klopstock and Bockenheimer 1904, and 

 Koch 1908) reported that they could be sharply divided into two types — the patho- 

 genic and the saprophytic types. The great majority of strains isolated from 

 purulent lesions in the human body were agglutinated by a serum prepared 

 against one such strain, whereas the strains isolated from saprophytic sources 

 were not agglutinated. The difference in titre to which agglutination occurred 

 rather suggested that there might be one or more sub-groups within the main 

 types. This suggestion was confirmed by later workers, who employed the more 

 delicate test of absorption of agglutinins. Thus Julianelle (1922) found that the 

 staphylococci could be divided into three types with two sub-groups, whereas Hine 

 (1922), working with 81 strains, was able to classify them into two main types, 

 each of which had at least three sub-groups. There was evidence to suggest that 

 the pathogenic strains formed a more homogeneous serological group than the 

 saprophytic. 



More recently, Yonemiira (1936) examined 324 strains from pathological sources and 

 was able by the use of absorbed sera to divide them into nine main types ; aU but 22 

 of the strains, however, fell into three of these types. Blair and Hallman (1936) recog- 

 nized three types by the absorption of agglutinins method. Cowan (1938, 1939a) hke- 

 wise showed that it was possible by sUde agglutination, using absorbed sera, to distinguish 

 three main types among the pathogenic staphylococci ; there is reason to beheve, however, 

 that each of these contains sub-types distinguishable by means of absorbed sera (Christie 

 and Keogh 1940). Working in India, Goyle and Minchin (1940) were able to classify 

 only 33 per cent, of pathogenic strains by Cowan's method. Considerably more work 

 will have to be done before the serological t3rping of staphylococci becomes of much 

 practical use in epidemiological investigations. 



Julianelle and Wieghard (1934, 1935), and Wieghard and Julianelle (1935), as the 

 result of chemical fractionation of staphylococci, have isolated two polysaccharides 

 each containing about 4 per cent, nitrogen, and distinguished from each other 

 by optical rotation and by the type of sugar produced on hydrolysis. The first 

 polysaccharide was extracted from pathogenic (A), the second from non-pathogenic 



