THE MORPHOLOGY OF BACTERIA 13 



spore swells and becomes less strongly refracting ; then one end 

 of the spore ruptures and an opening forms, as if by absorption 

 of the spore membrane at this point, and the germ rod emerges. 

 The latter then elongates, and the membrane either remains 

 attached to the rod or is cast off. The process is shown in 

 Fig. 6, A and E, and the figures 1-4 show the successive stages. 

 In Bact. sessile, as shown at F in the same figure, the germinal 

 rod proceeds from both poles of the spore. This may be desig- 

 nated bipolar, as distinguished from unipolar germination in 

 the former species. Equatorial germination is illustrated in B. 

 subtilis by Prazmowski, and in B. tumescens and in B. carota- 

 rum after A. Koch. Here the process is as before, except that 

 the germinal rod emerges in a direction at right angles, or ob- 

 liquely to the longer axis, or in a generally equatorial direction, 

 as shown in Fig. 6, B, C, and D. Germination by absorption is 

 illustrated in B. leptosporus by Klein, and in Bact. anthracis by 

 De Bary. In the former species the spores are long, strongly 

 refracting, and surrounded by a wide capsule. At the beginning 

 of the germination the spore thickens, then elongates, and be- 

 comes darker at the poles ; the membrane gradually disappears 

 by absorption and the spore passes into a vegetating rod. A 

 similar process has been noted in Bact. anthracis, see Fig. 6, H, 

 i, 2, 3, 4. Endo-germination. According to Sorokin, Spirillum 

 endoparagogicum shows a unique method of germination. Here 

 the spores germinate within the body of the parent cell, as seen 

 in Fig. 6, G. The germinal rod then becomes detached, leaving 

 the empty capsule within the parent. 



The Study of Spore Germination. Students should endeavor 

 to study the method of spore germination in all species which 

 they are led to investigate. A satisfactory method is to intro- 

 duce a quantity of spores into a small portion of bouillon, and then 

 make cover-glass preparations of the latter at intervals of 30 

 minutes, using -Loffler's alkaline methylene blue, without heat, 

 as a stain. 



