10 



as 10 per cent, gelatine. The whole tube is liquefied in from 2-4 weeks' growth. 

 The liquid becomes yellowish in color and gives ofi a peculiar odor. Kla- 

 maunn states that in gelatine acidified with lactic acid the gro wth is slow 

 and l^ng threads are formed. 



Gelatine Streak Cultures. — In gelatine streak cultures the appearance is 

 very similar to what one sees in stick cultures. The bacilli first grow along 

 the line of inoculation ; and then throw out shoots into the surrounding 

 gelatine, producing the appearance noted in the stick culture. The bacilli 

 move to and fro along the channels of liquefied gelatine, 



Agar plates. — On agar plates at 37" 0., the colonies at the end of eight 

 hours are small and burr-like, with spines protruding in all directions, giving 

 the colony the appearance of a sea-urchin. In some cases the projections are 

 from one side or end. At the end of 12 hours, the colonies have well-defined 

 projections, visible to the naked eye. The colonies in the depths of the agar 

 are more spiny, the processes being much shorter. On agar plates streaked 

 with a light inoculation, most beautiful forms occur. The growth of the 

 bacilli spreads over the surface and branches repeatedly, giving the appear- 

 ance of s'aweed. Thi"; appearance is distinctively characteristic ; and as the 

 growth is very rapid, this method commends itself for making a quick diag- 

 nosis of the presence of the bacillus in larv% supposed to be diseased. 



Potato cultures. — On potatoes the growth diifers considerably, according 

 to the reaction and age of the potato. Sometimes a brownish wrinkled 

 growth forms, which gives oflF a peculiar odor j at other times a dryish yellow 

 layer appears, " The bacilli grow very slowly indeed at 20" 0." (Oheyne 

 23.) Even at 37' C. they grow slowly. 



Milk. — In milk at 37° C, coagulation of the casein occurs in three 

 days. The milk becomes yellowish and gives off a characteristic odor. 

 After several week's growth, the curd is digested and a whey-like fluid 

 remains. 



Blood serum. — On blood serum at 37° , the growth is rather slow and 

 polymorphic forms are common. " Very long filaments are formed " (23). 

 These long forms may be from 5 to 10 times as long as the average bacillus 

 growing on gelatine, and consist of single cells. The filaments are often 

 wavy or twisted and of unequal thickness. The extremities of the long, bgnt 

 rods are often clubbed ; and y-forms are numerous. Spores are formed very 

 sparingly, and the blood serum is liquefied. 



Synthetic media ( UschinsJcy). — In Uschinsky's medium no growth occurs ; 

 but if the medium is neutralized, good growth ensues. The bacilli occur in 

 threads and a pellicle is formed. 



Dunham's Solution. The bacilli are small when grown in this solution; 

 No threads form ; but there is a slight indol reaction after nine days' growth. 



Relation to Free Oxygen. Cheyne states that the germs grow most 

 rapidly on the surf«ce of agar and arrange themselves side by side ; and they 

 produce spores in this position after a few days' growth. Eisenberg (39) says 

 nothing under the head of aerobiosis. Howard (40) writes that, " It grows 

 best under anaerobic conditions ; is a facultative aerobe ; grows under the 

 mica plate ; and in the presence of oxygen the growth is slight and slow." 

 Howard also states that under anaerobic conditions it emits a foul odour re- 

 sembling that of foul brood. It will be thus seen that Cheyne and Howard 

 do not agree on this point. The former author also says that the character- 

 istic odour is given oS under aerobic conditions, whilst Howard states that 

 this smell is emitted under anaerobic conditions. Further, Cheyne states 

 that the bacilli grow with great rapidity on the surface of agar, whereas 



