GENERAL SYSTEMATIC BACTERIOLOGY 499 



Tetracoccus. A form genus used by Billet (1890, p. 24) to designate 

 cocci which occur in fours. The name is rejected by E. F. Smith 

 (1905). Miquel (1891) also used this generic designation. 



Apparently the first use in a binomial was by Klecki (1894, p. 354) 

 who described a species Tetracoccus butyri from rancid butter. 



An independent introduction of a genus name Tetracoccus is that 

 of Orla-Jensen (1919, p. 154). He says: 



In this genus (Table XXVII) I include all sugar-fermenting micrococci and 

 sarcinae. From the sugar they form, besides lactic acid, smaller or greater quan- 

 tities of acetic acid. The quantity of lactic acid was in many cases so small that 

 we were not able to determine with certainty of what sort it was. As they thus 

 stand at the limit of what we will term lactic acid bacteria, we have not sought for 

 them systematically, as for the cocci already described, and thus make no claim 

 to have found, even approximately, representatives of all species belonging 

 thereto, but merely of some of those most frequently met with in the dairy. 



The first species named is Tetracoccus liquefaciens (Micrococcus 

 casei liquefaciens Orla-Jensen). Others named are Tc. casei, Tc. 

 mastitidis, Tc. 'pyogenes aureus, Tc. pyogenes albus and Tc. mycoder- 

 matus. 



Later (1921, p. 268) he states: 



The acid forming micrococci and sarcinae I have brought together in the 

 genus Tetracoccus, as I believed it to be quite as wrong to draw a limit between the 

 micrococci and the sarcinae as between the short- and long-chained streptococci. 



Tetradiplococcus. Bartoszewicz and Schwarzwasser (1908, p. 614) 

 proposed the name Tetradiplococcus filiformans lodzensis. The or- 

 ganism was isolated from the Lodz tap water by means of plate culture. 

 In hanging drop the organism appears alw^ays in the form of tetrads 

 so constructed that each element of the tetrad is a diplococcus. Each 

 cell has the form of the gonococcus. The tetrads are actively motile 

 in 3'oung cultures, but flagella could not be demonstrated. The 

 tetrads are 4 to 6^ in diameter. The organism grows well at room 

 temperature, but much better at 30 to 37°. Gelatin is not liquefied. 

 The most conspicuous growth character is the formation of slender 

 filaments in broth which rise from the bottom of the tube toward the 

 mouth. The filaments do not develop well at room temperature. The 

 broth remains clear, but there is a gelatinous deposit. In stab cul- 

 tures in agar a fir tree growth develops. Plate colonies are small, 

 white granular known on the surface. Gelatin kept at 30° shows the 

 filament formation well. Practically an obligate aerobe. The cells 

 are Gram-positive. 



