SOIL ACTINOMYCES 297 



and cellulose 26 serve as good sources of carbon only for certain species. 23 

 Various organic acids, such as succinic, malic, tartaric and citric, are well 

 utilized, but formic, acetic, propionic, butyric, valerianic, lactic, benzoic 

 and oxalic are not well utilized. 24 Proteins and amino acids can readily 

 be used as sources of carbon. 25 Lieske 27 employed a solution of 1 per 

 cent urea, traces of K 2 HP0 4 and MgS0 4 and 2 per cent of the corre- 

 sponding carbon source in distilled water. He found that the aerobic, 

 saprophytic strains utilized maltose, lactose, levulose, dextrin, glucose, 

 glycerin, glycogen, inulin, mannite, asparagine, human blood serum, 

 and sucrose with decreasing efficiency in the order named. Only one of 

 the two strains utilized starch and none utilized cellulose. Failure to 

 obtain growth with cellulose is more often due to the fact that the 

 proper method has not been employed. Utilization of cellulose should 

 be tested on the agar plate 28 with reprecipitated cellulose or by adding 

 cellulose to sterile soil. The same is true, to a less extent, of the 

 utilization of starch which was found to be one of the best sources of 

 energy for the majority of actinomyces (except a few human patho- 

 genes). Some strains utilize ethyl and methyl alcohol and, to a small 

 extent, tannin. Amygdalin, caffeine, sodium soap and potassium ace- 

 tate may also be assimilated. 27 



Actinomyces can multiply in sterile butter fat; growth is accompanied 

 by a definite increase in acidity. 29 By the use of a modification of Eij Io- 

 nian's method, it was demonstrated that a large number of actinomyces 

 are able to produce fat splitting enzymes. 27 This was accomplished by 

 adding 1-3 per cent of the fat to the molten agar, shaking well, pouring 

 plates, then inoculating. On adding an indicator, such as litmus or 

 brom phenol blue, no acidity could be indicated. The fatty acids are 

 neutralized as can be readily demonstrated by the formation of crystals 



23 Waksman, S. A. Studies in the metabolism of actinomycetes. II. Carbon 

 metabolism. Jour. Bact., 4: 307-330. 1919. 



24 Salzmann, P. Chemisch-physiologische Untersuchungen liber die Lebens- 

 bedingungen von zwei Arten denitrifizierender Bakterien und der Streptothrix 

 odorifera. Diss. Konigsberg. 1901. 



25 Miinter, F. Uber Aktinomyceten des Bodens. Centrbl. Bakt. II, 38: 

 365-381. 1913. 



26 Krainsky, A., 1914 (p. 28S). On the decomposition of cellulose by micro- 

 organisms. Zhur. Opit. Agron., 14: 255-261. 1913. 



27 Lieske, 1921 (p. 288). 



28 Scales, 1915 (p. 265). 



29 Jensen, O. Studien iiber das Ranzigwerden der Butter. Centrbl. Bakt. 

 II, 8: 171. 1902. 



