Chapter I — 21 — Taxonomy 



reaction corresponded well to the agglutination reaction. The agglutinating re- 

 ceptors were present more abundantly in the spores than in the mycelium. V. 

 Magnus (282) has been able to separate various strains of actinomycetes, on a 

 serological basis into acid producers, alkali producers and neutrals; hemoagglutina- 

 tion phenomena were found to occur among 80 per cent of tiie acid producers. 



8. Phage specificity. Certain actinomycetes are subject to attack by specific 

 phages; thus, one actinophage attacks only the streptomycin-producing strains of 

 S. grisens, and not others. 



Biocheuiical characteristics.— This group of properties comprises 

 quantitative rather than quahtative differences. The S. coelicolur 

 group, for example, was found (78) to include forms which differ 

 greatly in type of pigment produced. 



1. 

 Fig. 5 d (see p. 18). 



On the basis of the reduction of nitrate to nitrite, the actinomycetes 

 have been divided (134) into three groups: (a) those that give little or 

 no reduction; (I?) those that give moderate reduction; (c) those that 

 give strong reduction. A similar basis of separation might be suggested 

 for the properties of proteolysis, amvlolvtic action, and sucrose inversion. 

 The ability to utilize specific carbohydrates is another biochemical prop- 

 erty characterizing different types of organisms. 



On the basis of these various properties, one may feel justified in 

 establishing distinct species within the various genera. 



