28 GENERAL DEATH-RATE FOR ALL AGES, ETC. 



regions of the earth's surface, and fluctuating in a 

 wave-like rise and fall of longer or shorter cycles, as 

 in the well-known fluctuations of magnetic variations 

 and sun-spot intensities ; favourable or unfavourable 

 conditions in different regions,intensifying or diminish- 

 ing the general effect, but not altogether dissipating 

 its influences. 



As regards the first of these (human action or inaction) it 

 needs only to be mentioned to be at once rejected ; for 

 -whatever value we may ascribe to the ameliorating influence 

 of human action in improving sanitary and other conditions 

 connected with health and the treatment of injury or 

 disease, and thus lessening the severity of attacks of disease, 

 whether epidemic or endemic. Still we can hardly conceive 

 that men's minds and action should act in concert, consciously 

 or otherwise, in all local centres over many countries so as to 

 produce a rhythmic result upon local health, corresponding to 

 the rhythmic rise and fall observable in the actual death-rate 

 of countries widely separated during many years. 



It must be borne in mind that knowledge tends always to 

 increase, and improvement must needs follow in one direction, 

 however slow it may be. Action, though fitful, always fol- 

 lows upon increasing knowledge; and although it may be 

 more than counterbalanced by the tendency of people to 

 become unduly aggregated in old or new centres, still the 

 failure to advance with increasing needs would not result in 

 such rhythmic rise and fall m relation to the generally improv- 

 ing provisions, so as to agree with the death-rate cycles 

 referred to. 



Again, the habit of referring any unusual epidemic 

 visitation to a chance medium for its communication from a 

 distant endemic centre, either by infection or contagion, is a 

 most unsatisfactory explanation. 



This only places us a link further back in a possible chain 

 of causation. Is it true that the channels of communication 

 from endemic centres are only open to infection or contagion 

 at periods corresponding to local death-rate cycles ? Even if 

 -we admitted this in some cases, it would still leave us without 

 an answer in respect of the fluctuations of intensity over well- 

 ■ marked cycles, in the very centres where a specific disease is 

 endemic and never wholly absent. 



The only natural explanation of these extraordinary 

 fluctuations, as regards origin, is to refer them to unknown 

 or obscure cosmical influences, the sum of which may 

 harmonise with the known periodicity of the death-rate 

 occurring simultaneously in countries wide apart. This 

 reference is justified by analogy, with known modes of 

 cosmical or superterrestrial disturbance. For example, we 



