IMPORTANCE OF PROCESS IN CLASSIFICATION 55 



A unique procedure is manifested in the germination of the spores of Spiril- 

 lum endoparagogicum, the membrane of the mother-cell remaining unimpaired 

 (as already mentioned) after the spores are formed, so that the germs proceeding 

 from the spores have to penetrate the membrane of the mother-cell in order to 

 attain their freedom. Not infrequently they remain attached by the one end, 

 thus giving rise to a branched form, as shown in Fig. 27. 



59. Importance of this Process in the Classification of Bacteria. 



Since, according to observations made thereon, the course of spore germina- 

 tion differs in the various species, it may be utilised, in the characterisation of 

 species, as an invariable and therefore reliable indication. One example, serving 

 for Bacteriology in general, may here be cited. H. BUCHNER (II.) ascertained 

 that by a suitably modified method of culture it was possible to deprive the 

 anthrax bacillus of its virulence and render it harmless. Sundry other experi- 

 ments (subsequently found to be defective and deceptive) with the hay bacillus 

 (B. subtilis) induced him to assert that these two 

 species were identical, the hay bacillus being an 

 anthrax bacillus that had lost its virulence, and vice 

 versd. Now it has already been shown that the 

 germination of the endospores of B. anthracis 

 follows a different course to that occurring in B. 

 subtilis; consequently, if the former were by 

 Buchner's treatment not only rendered harmless, 

 but also actually converted into B. subtilis, then the 

 course of germination must also have become corre- 

 spondingly changed. Starting with this assump- 

 tion, PRAZMOWSKI (III.) subjected a weakened 

 anthrax bacillus (presumably transformed into B. 

 subtilis) to examination with regard to the nature 

 of the formation and germination of its spores. 

 He found that both operations pursued exactly 

 the same course as in the virulent (unweakened) 

 anthrax bacillus, thereby disproving the assump- 

 tion of the identity of the two species. 



The first observation of the production of de- 

 veloping reproductive cells within the bacterial cell 

 was made by PERTY (I.) in 1852, who designated 

 the rods he found to possess this property Sporo- 

 nema gracile (Fig. 28). His communication, 

 however, met with no recognition and fell into 

 oblivion. About fifteen years later PASTEUR ("VI.), 

 unaware of Perty's observation, re-discovered the 



same fact in the course of his researches on the causes of lethargy in silkworms 

 (gattine). The fission fungi which he found in large number in the alimentary 

 canal of the diseased (lethargic) worms, and which he experimentally ascertained 

 to be the cause of this generally fatal epidemic, frequently exhibited internal 

 lustrous enclosures, the formation and function of which he explained to be 

 reproduction by endogenous germs ("reproduction par noyaux interieurs"), 

 without, however, observing them more closely in order to ascertain the accuracy 

 of this hypothesis. 



Only one proof was needed to set this beyond doubt, namely, the 

 demonstration that these forms have the faculty of germinating and of develop- 

 ing into new individuals. FERD. COHEN (VII.) first succeeded in doing this, in 



FIG. 28. 

 Spore formation according to Perty. 



b-g. Sporonema gracile ; b. with one 

 terminal spore ; c. with two spores ; 

 in d the spore has escaped from the 

 mother-cell ; e-g shows the gradual 

 development of the spore until 

 ripe. In a is shown the (formerly) 

 so-called Metallacter, a chain of 

 short threads which when viewed 

 under a low power is apt to be 

 mistaken for a long rod, hence its 

 name. 



