278 BIOLOGICAL PROBLEMS 



But I must not close this reference to army experi- 

 ences without referring to a recent experience in the 

 American army. In December, 1916 (as recorded in 

 The Military Surgeon), a division of the United States 

 army was under canvas in Camp Wilson, Texas. 

 The great prevalence of respiratory diseases led to a 

 conference of medical officers, at which it was agreed 

 that better ventilation and airing of the tents was 

 indicated. The co-operation of regimental commanders 

 varied, and the prevalence of respiratory diseases, 

 and of measles, closely conformed to these variations. 

 Although nearly 14,000 men were occupying the same 

 camp during the same period of observation, some 

 units had a high sick-rate from respiratory diseases 

 and measles, and others a low rate, and ventilation 

 was found, after a close and skilled enquiry, to have 

 a similar effect upon measles incidence as it had upon 

 respiratory diseases, namely, it reduced both. It was 

 also found that cold weather and rain favoured re- 

 spiratory diseases among the troops by causing them 

 to herd together in the huts. It is the stoves which 

 attract the men, and these lead to an increased draught 

 from any open window, and so this gets closed. 



A very fatal disease which we in this country have 

 had opportunities of bringing under proper scientific 

 investigation only in quite recent years is cerebro- 

 spinal fever or " spotted fever". The testimony to 

 the value of fresh air in the prevention of this disease 

 is very striking, and when spotted fever occurs we 

 have learnt from experience the value of better spacing 

 out and more fresh air in reducing its spread. The 

 value of better ventilation in cerebro-spinal fever is 

 partly due to the cooler air thereby secured, for the 

 specific germ dies so rapidly in cool air that the 

 chance of the spread of infection is thus reduced, 

 but the fresher air probably acts chiefly by " keying 



