CHAPTER VI. 



THE GERMINATION OF THE ENDOSPORE. 



56. First Type. 



WHEN the spore is exposed to favourable conditions as regards nutrition, it 

 abandons its dormant state and begins to germinate by commencing to absorb 

 liquid from the surrounding medium. It then becomes distended, its high 

 refractive power gradually diminishing in the same proportion. Further 

 development can then proceed in three ways. 



The first type of spore germination was accurately observed by H. BUCHXER 

 (III.) in Bacillus anthracis, the producer of anthrax, and afterwards discovered 



'( oiO<*c<f*<3rt 



*** 



FIG. 21. FIG. 22. Clostridiuin butyricuui. 



Bacillus anthracis. Spore formation. 



Germination of spores. ripe 8 po rei 



s. the ripe spore before b. ditto expanding in nutrient solution. 



germination begins; i, c. final dimensions attained, and separation of 



2, 3. three successive exosporium from endosporium visible, 

 stages of germination ; rf, e. young rod escaping from pol-ir extremity 



3. the fully developed of spore capsule. 



rod. (After De Bary.) (After Pra~mowski.) Magu. 1020. 



Magn. about 600-700. 



in other kinds ; as, for instance, by PRAZMOWSKI (II.) in a fission fungus named 

 by him " mistbakterie " (dung bacterium), and in a second species isolated from 

 fermenting urine. The progi-ess of germination in this type is very simple 

 (Fig. 21). The spore, gradually acquiring the normal dimensions and functions 

 of the vegetative form, soon divides and reproduces by fission. According to 

 several observations made by Brefeld, the external layer of the spore-membrane 

 (" exosporium ") separates during this germination process and swells up. This 

 harmonises well with the remark made in a previous paragraph, that the spore- 

 capsule probably consists of two layers, distinguished as exosporium and endo- 

 sporium. 



57. Second Type of Spore Germination. 



Microscopically the initial stage of the process is identical with that described 

 in the foregoing paragraph ; the refraction of the spore diminishes and an in- 

 crease in size occurs. Then, however, the contents of the spore are elaborated 

 into a new rod, which is surrounded by a thin membrane, and which, by its 

 further growth, bursts the spore capsule. 



This rupture is effected at the point of least resistance, the position of which 

 and consequently the mode of escape of the germ varies in different species. 



In Clostridium butyricum, Cl. Polymyxa, and a few others, the spore capsule 

 opens at one of the poles, so that the direction taken by the young rod in its 

 escape is in a line with its length, as shown in Fig. 22, d. The expulsion is 



52 



