288 PRINCIPLES OF SOIL MICROBIOLOGY 



and possessing false branching. The individual cells may, in the case 

 of both Leptothrix and Cladothrix, leave the sheath and take the form 

 of swarmers possessing flagella. When a swarmer attaches itself to an 

 old thread and develops into a new thread, false branching arises. 

 Oospora and Oidium are names of true fungi, which have nothing in 

 common with the actinomyces. The term Discomyces was used in 

 1875 in an imperfect description of actinomycosis of cattle. Nocardia 

 was used in 1889, long after the term Actinomyces had been introduced 

 by Harz in an accurate description of the cattle disease; that term is, 

 therefore, without any scientific foundation. A number of investigators 

 still adhere to these terms, especially to that of Discomyces 2 and Nocar- 

 dia. 3 The term Streptothrix, which has been used very often in desig- 

 nating true actinomyces, is invalid due to the fact that it was pre- 

 empted by Corda, in 1839, for a true fungus. 



The term Actinomyces was used first by Harz 4 in 1878 in describing 

 the actinomycotic disease of cattle. He applied this term, which means 

 "ray-fungus," because of the formation of bottle-shaped and ray-like 

 swellings of the threads of the Actinomyces granules in the actinomycotic 

 disease of cattle. This term has been accepted in all the leading recent 

 important investigations on this group of organisms, both pathogenic 

 and saprophytic forms. 5-10 A detailed discussion of the terminology 

 of this genus is found elsewhere. 11-13 



2 Merrill, E. D., and Wade, H. W. The validity of the name Discomyces for 

 the genus of fungi variously called Actinomyces, Streptothrix and Nocardia. 

 Phillip, Jour. Sci., 14: 55-69. 1919. 



3 Mello, F. de, and Fernandes, J. F. S. A. Revision des champignons ap- 

 partenant au genre Nocardia. Mem. Asiatic Soc. Bengal, 7: 103-138. 1919. 



4 Harz, C. O. Actinomyces bovis, ein neuer Schimmel in den Geweben des 

 Rindes. Jahresber. Tierarzneischule, Miinchen, 1877-78, 125-140. 



6 Krainsky, A. Die Aktinomyceten und ihre Bedeutung in der Natur. 

 Centrbl. Bakt. II, 41: 639-688. 1914. 



6 Waksman, S. A. Cultural studies of species of Actinomyces. Soil Sci., 

 8: 71-215. 1919. 



7 Conn, H. J. Soil flora studies. V. Actinomycetes in soil. N. Y. Agr. 

 Exp. Sta. Tech. Bui. 60, 1917. 



8 Drechsler, C. Morphology of the genus Actinomyces. Bot. Gaz., 67: 

 65-83, 147-168. 1919. 



9 Lieske, R. Morphologie und Biologie der Strahlenpilze. Leipzig. 1921. 

 10 Orskov, 1923 (p. 287). 



11 Lehmann and Neumann, 1921 (p. x). 



12 Lachner-Sandoval, V. tlber Strahlenpilze. Strassburg, Diss. 1898. 



13 Breed, R. S., and Conn, H. J. The nomenclature of the Actinomycetaceae. 

 Jour. Bact., 4: 585-602. 1919; 5: 489-490. 1920. 



