502 MALTA FEVER 



occurs irregularly scattered through the congested pulp ; it may 

 also be found in small numbers post mortem in the capillaries of 

 various organs. It may be cultivated from the blood during life 

 in a considerable proportion of cases ; for this purpose 5 to 10 c.c. 

 of blood should be withdrawn from a vein and distributed in 

 small flasks of bouillon. The micrococcus was found by the 

 members of the Commission in the urine of Malta fever patients 

 in 10 per cent, of the cases examined ; it was sometimes scanty, 

 but sometimes present in large numbers. It has also occasion- 

 ally been obtained from the faeces. 



Cultivation. — This can usually be effected by making stroke 

 cultures on agar tubes from the spleen pulp and incubating 



at 37° C. The colonies, 



^— r" \- ^ which are usually not 



•* ' # , \ visible before the third 



.1 . -m s or fourth day, appear as 



> * "j : ;• . *. small round discs, slightly 



» * ' - **, .'.'.<. ^ raised and of somewhat 



• •* s ,- ,-.." ' , '• transparent appearance. 



« *' \ * i • * The maximum size — 2 to 



. ' **7 ■ ; 'v» . 3 mm. in diameter — is 



\ % ... •-' ~,' reached about the ninth 



i'.* % * ■■'' day-; at this period by 



« T / reflected light they appear 



. •*" pearly white, while by 



* • *.'*'«*"" transmitted light they 



have a yellowish tint in 



Fig. 151.-Micrococcus melitensis, from a the centre > bluish-white 



two days' culture on agar at 37° C. at the periphery. A 



Stained with fuchsin. xlOOO. stroke culture shows a 



layer of growth of similar 

 appearance with somewhat serrated margins. The optimum 

 temperature is 37° C, but growth still occurs down to about 

 20° C. On gelatin at summer temperature growth is ex- 

 tremely 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 flocculent deposit at the 

 bottom; on the surface there is no formation of a pellicle. 

 The reaction of the media ought to be very faintly alkaline, 

 as marked alkalinity interferes with the growth; a reaction 

 of + 10 (p. 34) has been found very suitable. On potatoes 

 no visible growth takes place even at the body temperature, 



