HOW BACTERIA ARE NAMED AND IDENTIFIED 43 



(b) An adjective in the form of the present participle of a verb, as 

 Clostridium dissolvens (the dissolving Clostridium, in the sense of the 

 Clostridium which is able to dissolve), Bacillus adhaerens (the adhering 

 Bacillus), Acetobacter ascendens (the climbing Acetobacter) , Bacillus esterifi- 

 cans (the ester-producing Bacillus). The endings for present participles 

 used as adjectives are the same for all genders. The past participle is used 

 occasionally, as in Pseudomonas aptata (the adapted Pseudotnonas), Spiril- 

 lum attenuatum (the attenuated Spirillum). 



(c) A noun in the genitive (possessive) modifying the generic name. 

 There is no necessary agreement in gender or number. Examples, Clostri- 

 dium welchii (Welch's Clostridium.) , Salmonella pidlorum (the Salmonella 

 of chicks), Streptococcus lactis (the Streptococcus of milk), Brucella abortus 

 (the Brucella of abortion), Clostridium tetani (the Clostridium of tetanus), 

 Diplococcus pneumoniae (the Diplococcus of pneumonia). Salmonella 

 anatum (the Salmonella of ducks). 



(d) A noun in apposition, that is, an explanatoiy noun. This does not 

 agree necessarily with the generic name in gender. This method of naming 

 is relativeh^ not common in bacteriology. Examples are Actinomyces 

 scabies (the scurf or scab Actinomyces) , Bacillus lacticola (the milk-dweller 

 bacillus). Bacillus radicicola (the root-dweller bacillus). 



5. The author of the name is often indicated following the name of the 

 species, as Bacillus subtilis Cohn. Sometimes a name is indicated also in 

 parenthesis, as Micrococcus luteus (Schroeter) Cohn. This means that 

 Schroeter first named the species, giving it the name luteus, but placed it in 

 another genus {Bacteridium) . Cohn placed it in a new genus. It should 

 be noted that the name of a person, following the name of an organism is 

 frequently not the person who first discovered or described it, but the person 

 who first gave it the name used. For example, Clostridium welchii (Aligula) 

 Holland was first described by Dr. Wm. H. Welch, but not named by him. 

 It was named by Migula in honor of Dr. Welch and later it was placed in 

 the genus Clostridium by Holland. 



6. Sometimes species of bacteria are subdivided into varieties. These 

 are likewise given Latin designations, and the entire name written as: 



