PHILIP HADLEY 89 



the poles of the cell and represent the true bacterial nucleus or nuclei. After cell division the 

 heavily staining reserve substance soon appears in the daughter-cells. 



The first important departure from simple fission is gonidia formation. This form 

 of reproduction was first recognized and named by Cohn' in 1872 in his study of 

 Crenothrix, but the phenomenon was not carried over to the lower forms of bacteria. 

 Gonidia were also recognized Ijy Lancaster in 1873, and they were noted the same year 

 in B. lactis by Joseph Lister. They were also indicated in V . choJerae and in V . proteus 

 [Vibrio Jiuklcr- prior) by Finkler and Prior in 1885. Out of the gonidial bodies, which 

 were often regarded as spores, there were seen to arise extremely minute microspiral 

 forms which, through further development, eventually attained normal size. Since 

 these early days, gonidia have doubtless been seen many times without recognition. 

 They have been definitely reported by Jones, ^ Lohnis,' Almcjuist," Mellon, s Enderlein,*" 

 Tunnicliff,^ and others. Enderlein, who has been able to recognize them in many bac- 

 terial species, regards them as the most common seed form (Fruchtform) of bacteria, 

 being homologous with the spores of the fungi (conidia, ascospores). Morphologically 

 and actually, according to Enderlein, they represent the true bacterial spore, which is 

 not true of those elements usually termed "spores" by bacteriologists. 



Some of the so-called Much granules are regarded as gonidia, others as trophosomes. In 

 1870 Cohn differentiated gonidia into the large ("macrogonidia") and the small ("micro- 

 gonidia"). In the tubercle bacillus the microgonidia are not acid fast but may be gram posi- 

 tive. Enderlein mentions several sorts of gonidia, named according to their point of origin 

 in the cell. If they arise at the end of a rod, they are termed "telogonidia"; if throughout the 

 whole length of a rod, they are termed "ascogonidia." Apparently compared with such high- 

 er forms as Crenothrix, bacteria produce only small numbers of gonidia. That the micro- 

 gonidia may pass Chamberland filters seems to have been demonstrated by Lourens^ for the 

 bacillus of swinepest in 1907, by Almquist' for B. typhosus in 1911, by Miehe^ for a number of 

 bacterial species in 1923, and by Mellon^ for B. fusiformis in 1926. In other instances of the 

 discovery of filtrable forms of bacteria there is slight basis for an opinion as to the exact nature 

 of the filtrable unit; although, in the experiments of Fontes,^ who in 1910 was the first to 

 demonstrate the filtrability of the tubercle bacillus, the description of his cultures suggests 

 that the filtrable forms were microgonidia whose presence, among other small granular 

 bodies, he was unable to recognize. The telogonidia have been recognized in spirochetes 

 (Treponema and Leptospira) and may be concerned with the filtrability of organisms of this 

 class, as was first demonstrated by Novy and Knapp^ for the relapsing-fever spirochete in 

 1906, although it also appears to be true that fine spiral forms also may pass the Berkefeld 

 filter. According to Enderlein, the filtrable forms of bacteria comprise, not the gonidia 

 alone, but also the gonites, next to be described. 



Our knowledge of the bacterial reproductive elements known as the "gonites" is 

 limited to the results of Enderlein's'" studies, and particularly with reference to the 

 cholera vibrio. His observations, which are highly suggestive, but which naturally de- 

 mand extended confirmation, are presented forthwith. 



' See Hadley, Philip: loc. cit. ''Enderlein, G.: loc. cil. 



^ Jones, D. H.: /. Bad., 5, 325. 1920. '' Tunnicliff, R.: J . Infect. Dis., 36, 430. 1925. 



3 Lohnis, F.: loc. cit. ^ See Hadley, Philip: loc. cit. 



'• Almquist, E.: loc. cit. ' Almquist, E.: loc. cit. 



5 See Hadley, Philip : loc. cit. '» Enderlein, G.: Bakterien-Cyclogenie. Berlin, 1925. 



