330 MENINGOCOCCUS-^ONOCOCCUS— CATARRH ALIS GROUP 
blood or ascitic fluid, or upon LofRer's blood serum by smearing con- 
siderable quantities of cerebrospinal fluid (drawn with aseptic precau- 
tions by liun})ar punctm-e) in liberal amounts upon the surface of these 
media. 1 The addition of 1 per cent of glucose to the media (except 
those which are enriched with hemoglobin) favors development of the 
cocci. If the fluid obtained is not turbid, centrifugalization should be 
resorted to and the sediment distributed as densely as possible in the 
manner indicated. At the same time 5 to 10 cc. of blood should be 
drawn aseptically and added to 50 cc. of neutral glucose broth. A 
small lump of calcium carbonate (marble) seems to promote growth. 
The organisms are also present in the nasopharynx and may be ob- 
tained by plating material from swabs rubbed over the posterior 
nares.2 A few small, transparent, round colonies are usually obtained 
when relatively large amounts of material are inoculated. These 
colonies are usually from 1 to 4 mm. in diameter with smooth, sharply 
circumscribed margins, and the colony viewed under the f-inch objec- 
tive and 1-inch eye-piece is perfectly homogeneous. The first growth 
upon artificial media is difficult to obtain. Colonies may not appear 
until the third or even the fourth day after inoculation; secondary trans- 
fers, if made within three da}'S from initial cultivations, are usually 
successful and development is somewhat more vigorous. It should be 
emphasized that relatively large amounts of cocci must be inoculated 
to insure growth in artificial media.^ Ascitic and serum broths are 
suitable fluid media for the cultivation of the meningococcus. A 
coherent sediment gradually accumulates in these media and a delicate 
pellicle usually forms on the surface after a few days. Secondary 
transfers in milk usually grow, but there is little or no detectable change 
in the physical properties of the medium. 
The meningococcus is essentially an aerobic organism, at least in 
its development outside the human body. The optimum tempera- 
ture of growth is 37° C, and growth ceases when the temperature 
exceeds 42° C. or falls below 25° C. The organism is soon killed by 
low^ temperatures. Many unsuccessful attempts to isolate the men- 
ingococcus are due to the failure to keep the infected material at 
or near the body temperature continuously. Stock cultures cannot 
be maintained at the temperature of the ice-box; they should be kept 
at temperatures between 30° and 38° C. Frequent transfers (every 
two or three days) must be made to maintain the viability of many 
strains of the organism. A majority of strains, after the first few 
transfers upon artificial media, remain viable for several weeks upon 
the egg medium (p. 232) or the Eberson medium provided the tubes 
are sealed with paraffin and kept at 30° C. ; exceptionally strains are met 
with which become acclimated to the conditions obtaining in artificial 
' For technic of lumbar puncture, see page 25S. 
2 Davis: Jour. Infec. Dis., 1907, 4, 558. 
' The organisms, like gonococci, degenerate rapidly in artificial media. This may 
explain the necessity of transferring the organisms at frequent intervals. 
