196 Medical Bacteriology. 
1) Occurs in groups (cell-colonies) in pus-cells. 
2) Is decolorized by Gram’s method. 
3) Does not grow on agar at room or blood heat. (Foulerton). 
MICROCOCCUS INTRACELLULARIS. 
Pus may be obtained by lumbar puncture which is performed as follows. The back — 
of the patient and the operator’s hands should be made sterile. Theneedle (4cm. X 1 
mm. for children) should be boiled 10 minutes. The patient should lie on the right side, 
with the knees drawn up and the uppermost shoulder so depressed as to present the spinal 
column to the operator. The puncture is generally made between the third and fourth 
lumbar vertebrae. The thumb of the left hand is pressed between the spinous processes 
and the point of the needle is entered about 1 em. to the right of the median line, 
and on a level with the thumb nail and directed slightly upwards and inward toward the 
median line. Ata depth of 3 or4em. in children and 7 or 8 in adults the needle enters the 
subarachnoid space and the fluid flows usually by drops. This is allowed to drop into an 
absolutely clean test-tube, which has previously been plugged and sterilized. From 5 to 15 
ec. of the fluid is a sufficient quantity for examination. Cultures should be made at once on 
blood agar and plain agar (M. & W. 371.). After standing some hours, the sediment 
should be examined in cover-glass preparations, stained with Loeffler’s methylen blue 
and by Gram’s method. 
Micrococcus intracellularis stains by Loeffler’s method and appears as a diplococcus 
in groups in the pus cells, is decolorized by Gram’s method, and grows on blood-agar 
and feebly on ordinary agar at 38° C. 
The following organisms are also found occasionally. For methods of diagnosis see 
exercises indicated. 
cour. COIX. 
PNEUMONIAE. Stain for capsule. Cultivate on blood-agar. CVII. 
TUBERCULOSIS. OVII. 
LEPRAE-. For method of staining, see CV. 
MALLET. 
a, Widal reaction (If in man typhoid and diphtheria must be excluded in case of a 
positive reaction). 
b. Examination of discharge. 
1. Microscopical examination usually without result. 
2. Cultures, glycerine agar and potato from pus. 
ec. Animal inoculation, Straus method. 
B. PESTIS. 
a. Make plate cultures from blood and buboes and work up colonies. 
b. Make subcutaneous inoculation into guinea pigs from bubo, and if death ensues 
search for B. pestis. 
P. AERUGINOSA. Hasily recognized by its culture characters. 
B. WELCHII. 
This germ is non-pathogenic for rabbits but Welch and Flexner have shown that 
if a rabbit is inoculated intravenously with 0.5 to 1 cc. of a bouillon culture and killed 
after a lapse of 5 or 10 minutes and the animal kept at 18°-20° C. for 24 hours or at 
30°-35° C. for 4 to 6 hours, the organism will multiply in the blood and produce large 
quantities of gas in the vessels and organs. This effect is characteristic. 
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