THE GROUP OF THE PLECTRIDIAL ANAEROBES 557 
fluids. Mbrion septique, which is of about the same dimensions as 
B. sporogenes, exhibits distinctive invohition forms under similar 
conditions. 
The Gram-positiveness of the organism and the readiness with wliich 
it sporulates are also important morphological details. 
Cultural. —The striking features of B. sporogenes in cultural media 
are its luxuriant growth in media rich in protein but free from carbo- 
hydrate, and the dense, filamentous colonies it forms upon the surface 
of nutrient agar in the absence of air after an incubation period of two 
to three days. The rapid liquefaction of gelatin, coagulated serum and 
other protein-rich media is an important point of distinction. 
S^ro/oi/icfl/.— Agglutination of the organism with specific agglutinat- 
ing serum is of importance in establishing its identity. ' 
THE GROUP OF THE PLECTRIDIAL ANAEROBES. BACILLUS 
COCHLEARIUS, BACILLUS PSEUDOTETANUS (B. TETANO- 
MORPHOUS), BACILLUS PUTRIFICUS, AND B. PARAPU- 
TRIFICUS. 
A considerable number of anaerobic bacilli have been described which 
possess in common the ability to form terminal spores, greater in diam- 
eter than the parent (vegetati^•e) cells. These organisms give the 
organism an a})pearance which has been likened to a drum stick, or 
plectridium. pAcluding B. tetani, which forms a potent soluble toxin, 
and B. tertius, which is a relatively active fermenting organism flevoid 
of proteolytic powers, there remain several imperfectly described 
bacteria, among which four distinct published types are recognizable. 
Available information is insufficient to determine whether these types 
represent valid varieties of anaerobic microbes or whether these types 
are admixtures of two or even more symbiotes of similar morphology, 
which can persist as "pure mixed cultures" under conditions of arti- 
ficial cultivation for long periods of time. It is significant, in this 
connection, to realize the remarkable changes which published descrip- 
tions of B. putrificus, for example, have undergone, during the last two 
decades. Originally this organism was regarded as the only incitant 
of that type of chemical activity designated as "putrefactive;" now it 
appears doubtful if really pure cultures of this organism are even to be 
regarded as proteolytic. 
The tabulation on page 55S of the j)ublished characteristics of four of 
these end-spore forming bacilli is presented without the assurance that 
they will eventually be acceptable as definite anaerobic entities.' The 
descriptions rejjresent merely the present status of the types indicated. 
The names which are ordinarily attached to them are retained for 
convenience of identification. 
' The descriptions of Bacillus cochlearius and Bacillus pseudotetanus are probably 
less open to criticism than those of Bacillus putrificus and Bacillus paraputrificus. 
