Waksman — 190 — Actinomycetes 



could reduce gray mud to black mud, a process accompanied by move- 

 ment of calcium and iron to the upper mud layers. The precipitation 

 of CaCOs was said to be fa\'ored by the production of ammonia, which 

 changes the reaction of the medium to alkaline. Molisch (302) 

 included an Actinomyces among the organisms contributing to the pre- 

 cipitation of CaCOs. Sawjalow (386) also isolated from lake mud an 

 actinomyces (y4. pelogenes') which was believed to be capable of reduc- 

 ing sulfate to hydrogen sulfide. 



Actinomycetes as Causative Agents of Disease:— Actinomycetes, 

 unlike the bacteria and the viruses, are not responsible for any of the 

 great plagues that affect mankind and his domesticated animals. 

 Neither are they as universal agents of plant destruction as are many 

 fungi. Still, they are capable of causing certain important deep-seated 

 diseases that affect both the animal and plant kingdoms. The actino- 

 mycotic diseases of man and animals and the scab diseases of certain 

 plants, notably potatoes and mangels, point to their great potential im- 

 portance as disease-producing agents. 



Among the animal diseases, those brought about by anaerobic organ- 

 isms (actinomycosis) and those brought about by aerobic forms (no- 

 cardiosis) are frequently confused. The introduction of penicillin as 

 a chemotherapeutic agent has served to reduce the danger from these 

 infections, at least so far as man is concerned. 



The problem of plant diseases may sometimes reach alarming pro- 

 portions in connection with the highly important economic crop the Irish 

 potato. Scabbiness is favored by dry soil conditions, by an alkaline re- 

 action, and by a high humus content of the soil. On the other hand, 

 the use of organic fertilizers and green manures, especially under humid 

 conditions, serves to control this infection. In addition to potato scab 

 and mangel scab, a few other plant diseases, such as those of the sweet 

 potato, are caused by actinomycetes, but these are only minor in nature. 



Actinomycetes as Agents of Spoilage and Deterioration:— Ac- 



tinomvcetes may play a far more important role as agents of spoilage 

 than is commonly appreciated. This includes two phenomena: 1. 

 Deterioration of certain foodstuffs, which is largely caused by the im- 

 parting of characteristic earthy and pungent. flavors and odors to milk, 

 cacao, potable waters, and fish. In the case of the latter it is not the 

 direct infection of the fish but the tainting of their flesh due to the 

 absorption of the odoriferous substance from the water. 2. Staining 

 and actual destruction of certain fabrics, notably, woolens, cotton goods, 

 and paper. Actinom^'cetes cannot compare with the fungi as agents of 

 destruction of textiles under humid and high temperature conditions. 

 But even as slower-growing organisms, they can produce on cloth, cither 

 woolen or cotton, and on paper, especially in books, stains which reduce 

 considerably the value of the material. 



