T)ESCE1PTI0N OF SPECIES. 



519 



They form a vermilion layer on 

 potato. 



They -were isolated by Koch in 

 India from the intestinal contents 

 of an ape. 



Bacillus indigogenes (Alvarez). 

 Rods 3 fi in length and 1'5 jj. in 

 width, singly, and in chains ; capsu- 

 lated. 



On agar they produce a yellowish- 

 white layer, and are said to develop 

 an indigo-blue colour in infusions 

 of leaves of the indigo plant. 



Intravenous injections in guinea- 

 pigs are said to produce death in a 

 few hours. 



They were isolated from the 

 leaves of the indigo plant. 



Bacillus iudigouaceus (Clas- 

 sen). — Rods 1-6 to 3 n long, "8 to 

 •9 11 wide ; non-motile. 



They form a sky-blue layer on 

 the surface of gelatine. 



On potato the growth is dark- 

 blue, and later has a metallic lustre. 



Bacillus indigoferus, which was 

 found in water at Kiel, is only 

 to be distinguished by its motility. 



Bacillus inflatus (A. Koch).— 

 Rods 4'6 to 5 5 /i in length, '6 to 

 1"8 fi in width, and filaments. 



The colonies send out delicate 

 processes. 



The bacilli inoculated in the 

 depth of gelatine send out fine 

 filaments in the track of the needle 

 followed by slow liquefaction, 



On agar they form a shining 

 brownish layer. 



In broth a pellicle forms on the 

 surface. 



They occur in the air. 

 •Bacillus inunctus (Pohl).— 

 Rods 8'5 ft in length, '8 to -9 /x in 

 width. 



Inoculated in the depth of gela- 

 tine they grow both in the track of 

 the needle and on the surface ; 

 liquefaction follows in time. 



On agar they form a whitish 

 growth. 



They were isolated from the 

 water of marshes. 



Bacillus invisibilis (Vaughan). 

 — Rods ; motile. 



The colonies are irregular and 

 yellowish. 



Inoculated in the depth of gela- 

 tine they grow both in the track of 

 the needle and on the surface. 



On agar they form a white 

 growth. 



On potato they develop an in- 

 visible layer. 



They occur in water. 



Bacillus iridescens (TatarofE).— 

 Rods from 3'5 to 5-2 /x in length 

 and threads. Spore-formation pre- 

 sent ; slightly motile. 



The colonies have a characteristic 

 appearance recalling that of the 

 convolutions of the brain. 



Inoculated in the depth of gela- 

 tine there is a depression at the 

 point of puncture, and a thread- 

 like growth along the needle 

 track. 



On agar they form a thick, un- 

 even, moist, greenish-yellow, irides- 

 cent growth, with a pitted surface. 



Blood serum is liquefied. 



On potato there is a dry, thick, 

 dark yellow growth like honey. 



Broth is rendered turbid, and 

 there is a yeUow deposit. 



They are found in water. 



Bacillus lactis aerogenes (Es- 

 cherich). — Rods short and thick, 

 ■5 to 8 fi broad, and 1 to 2 ^ long, 

 with rounded ends ; usually in pairs 

 side by side and also in irregular 

 heaps. Non-motile ; spore-forma- 

 tion not observed. They grow best 

 at37°C. 



Colonies on the surface are raised, 

 moist, shining and porcelain- white. 

 Below the surface they have a 

 yellowish nucleus. 



Inoculated in the depth of gela- 

 tine the rods form an abundant 

 nail-shaped growth. On potato the 

 culture is composed of white colo- 

 nies, and bubbles are formed. The 

 colonies may coalesce and produce 

 a creamy layer. 



On blood serum there is a raised, 

 moist, shining, white growth. 



In milk sugar or grape sugar 

 solutions they produce gas. 



Injected subcutaneously in rab- 

 bits and guinea-pigs they cause 

 death in from one to three days, 

 and the bacilli are found in the 

 blood and internal organs. 



