224 Transactions of the Society. 



meningococcus. Gordon draws special attention to this feature, 

 and it seems to be one of considerable value in the process of 

 differentiation, though if the medium be "too rich" or too 

 stimulating, this failure of the organism to grow at the lower 

 temperature is not always observed.* The imperfect staining 

 of many of the meningococci, though already referred to, may 

 again be mentioned in connexion with a very curious feature 

 present in forty-eight-hour cultures taken from the throats of 

 contacts, i.e. individuals who have slept near and breathed the 

 atmosphere in a close and crowded hut where a virulent case of 

 the cerebro-spinal meningitis has occurred. In stained prepara- 

 tions made from colonies resembling the typical colonies de- 

 rived from cultures from cerebro-spinal flukl, whether basic dyes 

 or Gram's method be used, an enormous number of diplococci 

 remain practically unstained, and I think it is possible, though 

 as yet I have not collected sufficient evidence on this point, that 

 this feature may help in deciding whether we are dealing with 

 the meningococcus or not. It is recognized that it is neces- 

 sary to subculture the meningococcus every two or three clays, 

 or better still every twenty-four hours, at any rate until it 

 has had time to assume saprophytic characters, when, according 

 to Weichselbaum's pupils, the organism may remain alive and 

 active for months. Of that, again, I have as yet had no ex- 

 perience, but I have had too much experience of the readiness 

 with which it dies out under unfavourable conditions. This 

 delicacy has to be borne in mind when we come to consider 

 some of the problems still to be solved in regard to cerebro- 

 spinal meningitis. Speaking of the conditions under which this 

 disease occurs, I have already expressed the opinion that epidemic 

 cerebro-spinal meningitis occurs only where there are over- 

 crowding and bad ventilation, the bad ventilation being, I believe, 

 an even more important determining factor than the over- 

 crowding. We realize that epidemic cerebro-spinal meningitis is 

 no longer a jail fever, in civilized countries at any rate, as most 

 of the jails to-day are as well (or better) ventilated, as are most 



* Since the above was written, and with wider experience of cultures of the 

 meningococcus in different media, I have satisfied myself that Gordon is correct 

 in his contention that a special medium must be used if this temperature test is 

 to be relied upon, as the meningococcus cultivated on a medium too rich or 

 stimulating will, in many instances, grow at a temperature of 22° C. or 23° C, when 

 the same organism seeded on nutrose ascitic agar, though growing at 37° C, fails 

 to multiply at 22° C. or 23" C. Here, too, I must refer to Dr. E. M. Buchanan's 

 paper on the differentiation of the meningococcus from other Gram-negative diplo- 

 cocci that are met with in the nasopharynx of cerebro-spinal fever contacts 

 (Lancet, 1907, i. p. 1590), a paper that I had overlooked when the above was 

 written. It is certainly one of the most useful contributions to this subject that 

 has been made, and had I known of its existence, which I ought to have done, 

 it would have saved me a considerable amount of experimental work on reactions 

 of the meningococcus in media containing sugars, with neutral red as an indicator. 



