IIIS'I'OHICAL HAC'KCHOIM) 



13 



inu; this pc'riod, on \\w inctaholisin of the ;ic- 

 tiiioinycctcs, l)(><!;iniiiii^ willi the work of 

 Waksinan and his associates in I'll!) to li)'_M, 

 antl kviiliiif;' to nunuM-ous other in\('stiji;a- 

 tions in tliis licld. Stuihcs soon fohowcd on 

 the antaiionist ic a('1i\ili('s of act inoniycotcs, 

 notably tlic work of l^oi'ochihna (l!)oo), Xak- 

 hini()\-skaia (l!)o7), A\'aksnian and Foster 

 (1988), Ak^xopouios rl al. (I!);W), Krassii- 

 nikov and Korcniako (I!)o!)), and lunncrous 

 others. 



Th(> work of (Jratia and liis <;i()up on th(> 

 formation of l)a('teriolytie substances by cer- 

 tain actinoniycetes was foHowed by that of 

 Welsch on actinomycetin, a preparation con- 

 taininjj; an enzyme hirj>;ely responsible for 

 this activity. The studies of actinophage l)y 

 aetinomycetes were started w'ith the work 

 of Wiebols and Wieringa. 



The decomposition of organic materials, 

 ranging from complex substances in the form 

 of plant and animal residues in soil and in 

 composts to pure chemical compounds, in- 

 cluding celluloses, hemicelluloses, proteins, 

 and amino acids, received considerable at- 

 tention, particularly by the writer and his 

 students (Starkey and others). 



Information was also gradually accumu- 

 lating on the .systematic position and im- 

 portance of act inoiuNcetes in natuial proc- 

 esses. Sex'eral efforts were made to dexclop 

 a system of cla.ssification of ac^t inomycetes 

 thai would take into consideration much of 

 the accumulated information. The earlier 

 in\'(>stigalions on the cultural j)i"operties of 

 aetinomycetes, followed by the studies on 

 their morj)hology, and their aerol)ic and 

 anaeiobic modes of life, led to certain im- 

 jiortant systems of classification. The classi- 

 fication of aetinomycetes in the various edi- 

 tions of Bcrgci/'s Manual was based largely 

 upon cultural, biochemical, and certain mor- 

 phological pi-op(M'ties of the aetinomycetes. 

 It e\entually resulted in a working system 

 of classification, first proposed in 1940, and 

 finally codified (1943) by Waksman and 

 Henrici. 



The biological period was also character- 

 ized by important contributions to the 

 knowledge o'i pathogenic aetinomycetes, 

 notably the work of Erikson, \on Magnus, 

 Xaeslund, Cope, Rosebury, and others. The 

 strictly parasitic nature of the facultative 

 anaerobic Actirumiyces bovi.s and some of the 





Figure 9. Morphology of aetinomycetes compared to certain l^acteria and fungi with which they 

 have often been confused; f. to r., starting at top: Lcptothrix. Clndothrix, Streplubacillus, Oospora, 

 Oidium, Actinomyces (Reproduced from: Lieske, K. Morphologic mid Hiologie der Strahlenpilze. Verlag 

 von (Jebriider Borntraeger, Leipzig, 1921, p. 6). 



