510 THE ANAEROBIC BACTERIA 
features of the disease, and killed the animal, was performed by 
Carle and Rattone^ in 1884. The same year Xicolaier- demonstrated 
the tetanus bacillus in lesions induced in laboratory animals which 
were inoculated subcutaneouslv' with garden soil. It remained for 
Kitasato,^ however, to grow B. tetani in pure culture and to transmit 
the disease with these pure cultures to laboratory animals. 
Morphology.— B. tetani is a long, slender bacillus wdth rounded ends, 
measuring from 0.3 to 0.8 micron in diameter and from 2 to 6 microns 
in length. It occurs singly and in pairs in young, actively growing 
cultures. In older cultures the organisms occur in long chains not 
infrequently. Degeneration occurs in older cultures also; involution 
forms and free spores are formed freely under such conditions. Recently 
inoculated cultures exhibit slight motility and motile organisms possess 
from 60 to 80 peritrichic fiagella.'* Capsules have not been demon- 
strated. 
B. tetani retains the Gram stain, especially in young, active cultures; 
older cultures contain many organisms which not only become Gram- 
negative, they also fail to color uniformly with ordinary anilin dyes. 
Spores form readily under anaerobic conditions of culture; these are 
so characteristic in appearance they possess considerable diagnostic 
importance. The spores are spherical, terminal and greater in diameter 
than the vegetative cell. They measure from 1 to 1.5 microns in 
diameter. The spore at the end of the rod presents an appearance 
that has been likened to a drumstick, or plectridium. It should be 
remembered that other anaerobic bacteria, B. tertius, B. putrificus and 
paraputrificus, and B. cochlearius, also form terminal spores. The rate 
of spore formation in artificial media appears to be influenced materially 
by the temperature of incubation, and the composition of the medium 
in which sporulation occurs. At 20° C, spores appear within seven 
to eight days; at 37° C, they are usually found in large numbers after 
two to five days; at 43° C. the organisms grow slowly and form but few 
spores. Toxin formation is very slow at the higher temperature. 
Theobald Smith* has studied the resistance of spores produced under 
difl^erent conditions. In gelatin, sporulation is ^elati^'ely feeble (due 
to the lower temperature of incubation probably) and the resistance 
of the spores to physical agents is quite feeble. At the body tempera- 
ture, the spores which develop resist an exposure to flowing steam for 
forty minutes, and occasionally sixty minutes. Morax and Marie^ 
find that dried tetanus spores are killed by an exposure to dry heat at 
125° C. for twenty minutes. A 5 per cent solution of carbolic acid will 
destroy the \'iability of the spore in about ten hours; mercuric chloride 
• Giornale della R. acad. d. med, di Torino, March, 1884. 
2 Deutsch, med. Wchnschr., 1884, 10, 842; Iiiaug. Diss., Gottingen, 1885. 
3 Deutsche med, Wchnschr., 1889, 15, 6.35; Ztschr. f. Hyg., 1889, 7, 225. 
« Schwartz: Lo Sperimentale, 1891, p. 373. Votteler: Ztschr. f. Hyg., 1898, 27, 
480. de Grandi: Centralb. f. Bakteriol., orig,, 1903, 34, 97. 
6 Jour. Am. Med, Assn., 1908, 50, 929. 
« Ann. Inst. Pasteur, 1902, 16, 418, 
