We believe we should omit a complete description of the cultivation and identification of the meningococcus, as this would be too long. Whoever wishes to study this matter will moreover be unable to omit studying the works mentioned and the original literature cited in thein. Still it should be emphasized that the cocci are often limited in number and must be carefully sought in microscopical preparations. Nor is the cultural proof always easy, as these cocci do not grow at all on the common culture media, or at first they grow slowly and very delicately, transparent, and only gradually in progres.sive cultures show thick viscid colonies. In order to avoid the treacherous sources of error, it is advisable to follow the procedure of Heubner. With a sterilized pipette about 0.3 c.c. of the aspirated fluid is added to the water of condensa tion in an agar tube: after the tube has stood in the incubator 12 to 24 hours, the fluid is distributed over the surface of the agar by turning the tube. Then in 21-48 hours a rich growth occurs. From this first culture the propagation may then be carried on through many genera tions by simple inoculation.
The meningococcus intracellularis in nmny cases does not exist in pure culture, but mixed with other pyogenic cocci and bacteria, most frequently with Frankel's pneumococcus. Besides this, pyogenic ztaphylococci and streptocorci, sometimes influenza bacilli have also been found. Occasionally it occurs also in tuberculous meningitis as a secondary infection, in which case it seems not to influence the course of the disease.
It is always to be observed (which we desire briefly to remark), that there are various microorganisms (as, e.g., the micrococcus catarrhalis, Pfeiffer), which microscopically appear identical with the meningoeoccus and res,etnble it so closely in cultures, that only the most accurate in vestigation prevents errors.
In cases of meningitis the meningococcus has been found sometimes alone, sometimes with virulent pyogenie bacteria, more or less numerous ously present in most of the complications and also in the blood. In this connection the fact that it is frequently and richly present in the nasal secretion is most important, because its dissemination in the vicinity of the patient can only be from this source. Concerning its term of life and vital requirements outside of the human body the reports are so contradictory that no final decision can yet be pronounced.
Point of Entry.—The paths by which the meningococens intra cellularis enters the body are as yet not positively known. Based on the results of Weigert and Striimpell, who in their autopsies on cases of meningitis, had found pus in the pharynx and the adjoining cavities, the ethmoid plate was long eon.sidered the portal, and indeed the more
certainly, since it has been established by sufficiently numerous examina tions, that the meningococcus dwells on the nasal MUCOUS membrane of sound persons and persons continuing to be sound who were in the vicinity of the patient. However this mode of infection is no more proven than the mode just assumed by Mastenhoffer—the third tonsil: moreover we know that such pyogenic processes may occur in all possible severe infectious diseases.
Many circumstances indicate an hmatogenous infection of the meninges; however the source of the blood infection itself is still obscure.
The contagiousness of the disease is, as all experiences have shown, small in hospitals; but by no means to be underestimated, in unsanitary surroundings.
In barracks, prisons and in the dwellings of the poor, where cleanli ness is often wanting, sometimes numerous contact infections occur. On the other hand it has been demonstrated by Peterson, that the infectious matter may also persist in infected sick rooms and thus cause the disease.
At any rate the fact that, even under the most favorable condi tions, only relatively limited effidemies occur forces us to the conclusion that a few people only are susceptible to the disease. Why this is so is not known; often it is by no means the weakly ehildren that are attacked. We can only point out a few predisposing causes, which temporarily increase the suseeptibility of the individual. Continuous severe exposure to cold is occasionally mentioned; but it is more certain that even light cranial traumas (diving into water, Leyden: Riicken markskrankheiten, Berlin, IS74, Von. I), general concussions, sunstroke, physical and mental strain due to military marches, exaininations, etc., are strikingly frequent in the history of the case.
Concerning the epidemiology of the meningococcus little can be reported, since the germ has been recognized too recently and it is justly questioned whether all epidemics described as cerebrospinal meningitis are attributable to it. Beginning with the period LSGO-1870, greater or lesser epidemics of cerebrospinal meningitis have occurred periodi cally in various parts of Europe and North America, especially during the winter and spring. If these are distributed, as usually they were in recent years, very sparsely and in various districts of a metropolis, they of course appeared to individual observers to be sporadic eases, and not actually to be connected with an epidemic.