The President's Address. Bij G. S. Woodkead. 225 



modern dwelling-houses ; it is now essentially a disease of barracks, 

 ' ships and huts, and not of the open camp, though in bad weather, 

 and in good tents, the conditions for its development even under 

 canvas may not be wanting. Those who have had longest 

 experience of barrack life, and have profited by it, invariably 

 associate streptococcal sore throat with bad ventilation, for, 

 although you usually find little or no throat mischief in well- 

 ventilated huts, sore throats and catarrh abound in all those that 

 are badly ventilated, and I am satisfied that where throat mischief 

 abounds cerebro-spinal meningitis can gain a footing. Those who 

 have studied the history of epidemics of cerebro-spinal fever find 

 that it usually occurs in the late winter and the early spring, the 

 periods when men, to escape the cold, shut out fresh air, when 

 catarrh and throat mischief become rife and the protecting mucous 

 membrane of the upper part of the respiratory tract is damaged, 

 and when, especially after long-continued periods of wet and cold, 

 vitality is depressed, and the resisting power of the organism is 

 below par. I have long been satisfied that, especially in young 

 people, there is a close connexion between the tonsils, the 

 lymphatic tissue of the upper part of the naso-pharynx, and the 

 large lymph spaces near the base of the brain, and I believe that 

 the healthy lymphoid tissue in these positions acts as a filter 

 and prevents the invasion of the cerebro-spinal lymphatics by 

 various pathogenetic micro-organisms. When, however, such 

 defences are weakened or broken down, the organisms accumu- 

 lating in large numbers in the upper and posterior nares and fauces 

 may " break bounds " as it were and make their way by the finer 

 lymphatics into the cerebro-spinal spaces, and this whether the 

 organism be the tubercle bacillus, the meningococcus, a strepto- 

 coccus or the pneumococcus. Whether it be a lymphatic invasion 

 alone or whether it be lymphatic in the first instance, but 

 followed by an invasion of the blood vessels, I am not in a position 

 to offer any definite opinion, but that in its milder form it presents 

 but slight evidence of a hasmal infection, whilst in the more severe 

 cases it is distinctly septicemic in character, appears to be beyond 

 doubt. It is evident that the patient who has been a carrier for 

 some time may be attacked after his resisting powers have become 

 impaired, as he develops an attack of catarrh, is chilled and 

 depressed by a spell of cold weather, or as he is exhausted by 

 want of food, by over- exertion, by the lack of sleep or by an attack 

 of some minor ailment or secondary disease. The one great 

 comfort we have in all this is that the organism appears to be an 

 exceedingly delicate one, and that only under specially favourable 

 conditions is it capable of remaining alive for any length of time. 

 It is stated that a healthy individual may be a carrier for a 

 fortnight or three weeks, and that cases are recorded (though 

 owing to the difficulty of identifying the diplococcus doubt may 



