476 



Dr. G-. Thin. On Bacterium foetidum. [June 10, 



other by a yielding elastic substance, which is very faintly refractive, 

 complete the metamorphosis from the coccus to the rod. 



The development of the rod appears to take place in two directions. 

 In the one there is a formation of small segments whose fate it seems 

 to be to be set free from each other (fig. 6) ; whilst in the other a 

 formation of spores is introduced by a series of preliminary changes. 

 The latter process begins by a lengthening out of the rod, which is 

 frequently found of great comparative length. (These long rods are 

 naturally liable to be broken in the preparation, but an idea of their 

 length may be formed from fig 5, a.) 



After the rods have attained a certain length, the protoplasm 

 divides into separate portions in the tube (fig. 5, b, c) . Minute 

 refractive spheres then appear in the separate portions, but are also 

 found occasionally in a long rod before the protoplasm has separated 

 into segments (figs. 7, a, and 8, a). The delicate wall of the tube 

 remains in the meanwhile entire. 



The next stage is represented by tubes, in which the spores are so 

 densely packed, that they almost touch (fig. 8, 6), the wall of the tube 

 being, however, still visible. 



Two appearances, which were seen during the examination of 

 fresh specimens, but were not noticed in the permanent prepara- 

 tions, have not been drawn. I several times observed tubes filled 

 with spores, in which faint narrow lines of different refraction crossed 

 the tube between the spores, giving the impression of the existence of 

 a hyphen. I also several times observed tubes partially emptied of 

 their spores, the escaped spores lying beside the empty tube, and 

 resembling in every respect the spores still present in the portions 

 of the tube which had not ruptured. 



Amidst the mass of rods and tubes in all the different stages which 

 are found in the scum, were found dense masses of micrococci. When 

 they were set free by manipulation, and sufficiently isolated to be 

 accurately observed, they were found singly and in pairs (fig. 9), and 

 resembled in size and appearance, not only the spores which were 

 observed in the ripe tubes, but those which were found in the meshes 

 of the stocking. 



Several cultivations were made in turnip infusion from the original 

 stock and from various generations of the vitreous humour stock. No 

 regular notes were taken of these cultivations, but I can state that the 

 bacterium whilst it grows in turnip infusion grows less actively than 

 in vitreous humour. It took from three to five days (at the same 

 temperature at which the other cultivations were made) before a per- 

 ceptible scum appeared on the surface of the fluid, and then the scum 

 was not so thick as after a cultivation of half the time in vitreous 

 humour. All the lengths of rod formation were found, but in none 

 of the preparations examined did I find spores either in the long rods 



