THE BIOLOGY OF MICROBES, ETC. 133 



BACTERIA. 



Bacterium termo. The cells are oblong and 

 measure 1'5 n in length and about 0'5 //, in breadth 

 (Fig. 33, 15). Each cell is surrounded with a thick 

 membrane of cellulose (C 6 H 10 5 ) and a flagellum 

 at each end. Dr. W. H. Dallinger, F.K.S., has 

 measured the diameter of the flagellum of this 

 microbe, andjie finds that it is the aoAooth of an 

 inch, or expressed in decimals 0*00000488526 inch. 1 

 B. termo is one of the commonest forms in water 

 and putrefying fluids, but it always disappears when 

 putrefaction terminates, in fact it has been called 

 the microbe of putrefaction. It has remarkable 

 powers of vitality; it is most active between 32 

 and 36 C. ; at a temperature below 5 C. and 

 above 46 C. it does not produce putrefaction in 

 putrescible fluids ; however, above 50 C. it is killed, 

 but even at so low a temperature as 1 1 C. this 

 microbe is not destroyed. 2 It grows well on 

 bouillon, agar-agar, etc., and after several days' 

 incubation a pellicle is formed on the fluid medium. 

 When grown on solid agar-agar it imperfectly 

 liquefies the medium, and gaseous products are 

 generated. On sterilised potatoes B. termo produces 

 a slimy grey colony. It occurs singly, in pairs, and 

 zoogloea, and it is readily obtained by placing a 

 piece of meat in water kept in a warm place for a 

 few hours. It may be remarked that this microbe 

 has been considered to be only a phase-form of a 

 protean species. 



1 Journal of Royal Microscopical Society, 1878, p. 174. 



2 Giglioli's Fermentive Microbi, p. 50t , -^ v . 



I w IVZXwITj 



o- 



