450 MALTA FEVER. 



of a patient dead of the disease it occurs irregularly 

 scattered through the congested pulp. It may also be 

 found in small numbers post mortem in the capillarie's of 

 various organs, but examination of the blood during life 

 gives negative results. It can, however, be obtained by 

 puncture of the spleen during life. 



Cultivation. This can usually readily be effected by 

 making stroke cultures on agar tubes from the spleen pulp 

 and incubating at 37 C. The colonies, which are usually 

 not visible before the third day, appear as small round 

 discs, slightly raised and of somewhat transparent appear- 

 ance. The maximum size 2-3 mm. in diameter is 

 reached about the ninth day; at this period by reflected 

 light they appear pearly white, while by transmitted light 

 they have a yellowish tint in the centre, bluish white at the 

 periphery. A stroke culture shows a layer of growth of 

 similar appearance with somewhat serrated margins. Old 

 cultures assume a buff tint. The optimum temperature 

 is 37 C., but growth still occurs down to about 20 C. 

 On gelatine at summer temperature growth is extremely 

 slow after two or three weeks, in a puncture culture, 

 there is a delicate line of growth along the needle track 

 and a small flat expansion of growth on the surface. There 

 is no liquefaction of the medium. 



In bouillon there occurs a general turbidity with floccu- 

 lent deposit at the bottom ; on the surface there is no 

 formation of a pellicle. On potatoes no visible growth 

 takes place even at the body temperature, though the 

 organism multiplies to a certain extent. 



Relations to the Disease. There is in the first place 

 ample evidence, from examination of the spleen, both post 

 mortem and during life, that this organism is always present 

 in the disease. The experiments of Bruce and Hughes 

 show that by inoculation with even comparatively small 

 doses of pure cultures the disease can be produced in 

 monkeys. In these experiments seven animals in all were 

 used, in every case with a positive result. Four died at 

 varying periods of time, after showing well-marked fever, 



