Chapter XI — 173 — Human and Animal Diseases 



the form of leathery irregular colonies and producing a sediment in 

 liquid media; the other producing smooth, easily broken colonies on 

 sohd media and causing turbidity in anaerobic liquid media. These 

 two types were designated as the R- and S-forms, the first representing 

 the classical type of Wolf-Israel, and the second resembling typical 

 corynebacteria. Wright, however, believed that no significant differ- 

 ences existed between human and bovine strains Qsee p. 176). 



The aerobic disease-producing actinomycetes were believed to com- 

 prise an even larger number of organisms. The confusion thus created 

 was largely due to the difficulty of distinguishing between pathogenic 

 and saprophytic types. It is important to remember that pathogenic 

 forms are found only rarely among naturally occurring actinomycetes. 

 Serum reactions for establishing different types among disease-producing 

 actinomycetes have not always given the most satisfactory result. 



True actinomycosis is caused by an anaerobic or a microaerophilic 

 species. This organism brings about the formation of granulation tissue 

 and pus which contain the characteristic "Drusen" or "sulfur granules." 

 These granules consist of masses of hyphae which are arranged radially 

 and terminate in the form of eosin-staining clubs, consisting of material 

 which ensheathes the hyphal tips. Certain actinomycetes are kerato- 

 phytes in nature and have the ability to infect the human skin (317). 



Earlier Investigations:— Bollinger (42) was the first to observe, in 

 1877, the occurrence of an actinomyces in the pus from the swollen jaw 

 of a cow affected by "lumpy jaw." The botanist Harz examined the 

 filaments and the "sulfur granules" and proposed the name Actinomyces 

 hovis for the organism with its ray-like growth. Harz did not, how- 

 ever, obtain pure cultures of the infectiv^e agent. Ponfick (344) rec- 

 ognized actinomycosis in man in 1882, although the first detailed clini- 

 cal account of the infection in man was reported by Israel (181) in 

 1885, on the basis of 38 cases. 



Wolf and Israel (512, 513) were the first to make a careful 

 and comprehensive study of the organism concerned in actinomycosis. 

 They isolated from maxillary actinomycosis in cattle a culture which 

 they found to be a microaerophilic form, identical with the A. hovis of 

 Harz which is capable of growing at room temperature but grows better 

 at 30° to 37°C. Numerous minute, isolated dewdrop-like colonies 

 appeared on the surface of anaerobic agar slant cultures, the largest 

 colony being the size of a pinhead. The colonies gradually became 

 larger and formed ball-like, irregularly rounded, elevated nodules. The 

 colonies did not become confluent, and an apparendy homogeneous 

 layer of growth was seen to be made up of separate nodules. In some 

 cases, the colonies presented a prominent center with a lobulated mar- 

 gin, appearing in the form of rosettes. In stab cultures, growth was 

 sometimes limited to the lower portion of the line of inoculation or was 

 more pronounced there. In liquid broth, growth appeared under aero- 



