DESCRIPTION OF SPECIES. 



549 



blood and organs of cattle which 

 died of an epidemic disease asso- 

 ciated with haemoglobinuria. 



Helicobacterium aerogenes 

 (Miller). Bacilli singly, in chains 

 and long wavy filaments. Motile. 



Colonies whitish, varying in form. 



Inoculated in the depth of gela- 

 tine the bacilli give rise to a faintly 

 yellow growth in the track of the 

 needle, and an almost invisible, 

 rapidly growing layer on the 

 surface. 



On potato the growth is dry and 

 brownish. 



They were isolated from the 

 healthy intestinal tract. 



Leptothrix buccalis (Robin). 

 Long, thin threads, -7 to 1 /x broad, 

 colourless, often united in thick 

 bundles or felted together. Masses 

 of cocci occur with the threads, 

 and the threads themselves are com- 

 posed of long rods, short rods, and 

 cocci. The threads may break up 

 into spiral, vibrio, and spirochaeta 

 forms. The last-named occur in 

 large numbers in the mouth, and 

 have been named Spirochceta buc- 

 calis. Leptothrix buccalis is found 

 in teeth slime, and is believed 

 to be intimately connected with 

 dental caries. The threads pene- 

 trate the tissue of the teeth, after 

 the enamel has been acted upon by 

 acids generated by the fermentation 

 of food. The short rods, long rods, 

 cocci, leptothrix-forms, and screw- 

 forms are found in the dental 

 canals. 



The threads of Leptothrix buc- 

 calis have a special staining reaction 

 (Leber). They become coloured if 

 placed in an acid medium with 

 iodine ; if the medium be alkaline, 

 it must first be acidified with very 

 dilute hydrochloric acid or acetic 

 acid. The contents are stained 

 violet, and contrast with the sheath 

 and septa, which remain uncoloured. 



Leptothrix buccalis (Vignal).- 

 Rods 1 to 1-5 \i in width, 1-6 to 

 30 /u. in length. 



Colonies greyish-white, promi- 

 nent and furrowed. 



Inoculated in the depth of gela- 

 tine a filament forms in the track 



of the needle, and a growth occurs 

 on the free surface. Liquefaction 

 sets in at the upper part, forming 

 a cup-shaped cavity, and a bluish 

 skin floats upon the liquid. The 

 liquefaction gradually extends to 

 the side of the tube, and a deposit 

 is formed at the bottom of the 

 liquefied gelatine. 



On agar the layer is white, 

 wrinkled and transparent, and later 

 yellowish. 



In broth there is turbidity, but 

 no skin on the surface. 



On potato the growth is greyish- 

 white. 



They are occasionally present 

 in the mouth in health, and 

 are possibly identical with lepto- 

 thrix buccalis (Robin). 



Leptothrix gigantea (Miller). 

 Long rods, short rods and cocci 

 can be observed in the same thread. 

 There are also screw-threads, which 

 may take the form of spirals, 

 vibrios, or spirochaetae. The threads 

 increase in diameter from base 

 to apex ; corresponding with the 

 thickness of the threads, the rods 

 and cocci show different dimensions. 



They have been observed in the 

 diseased teeth of dogs, sheep, cats 

 and other animals. 



Leuconostoc mesenteroides, 

 Cienkowski (Gomme de siicrerie, 

 Froschlaichpilz, Frogspawn fungus). 

 Cocci and rods singly, in chains, 

 and in zoogloea, surrounded by a 

 thick gelatinous envelope. The life- 

 history has been very thoroughly 

 investigated. The spores, 1*8 to 

 2 p. in diam., are of a round or 

 ellipsoidal form, with thick mem- 

 brane and shining contents. The 

 outer membrane-layer bursts, and a 

 middle lamella oozes out, and forms 

 a thick gelatinous envelope, while 

 the inner layer remains adherent 

 to the plasma. Thus the spore- 

 germination leads to the formation 

 of a coccus with a gelatinous en- 

 velope. The coccus then elongates 

 into a short rod-form, and the 

 gelatinous envelope becomes ellip- 

 soidal. The rod divides into two 

 cocci, and each of these lengthens 

 into a rod and divides. By repetition 



